kmemtrace: SLOB hooks.

[linux-2.6/kmemtrace.git] / drivers / s390 / scsi / zfcp_erp.c

/*
 * This file is part of the zfcp device driver for
 * FCP adapters for IBM System z9 and zSeries.
 *
 * (C) Copyright IBM Corp. 2002, 2006
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define ZFCP_LOG_AREA                   ZFCP_LOG_AREA_ERP

#include "zfcp_ext.h"

static int zfcp_erp_adisc(struct zfcp_port *);
static void zfcp_erp_adisc_handler(unsigned long);

static int zfcp_erp_adapter_reopen_internal(struct zfcp_adapter *, int, u8,
                                            void *);
static int zfcp_erp_port_forced_reopen_internal(struct zfcp_port *, int, u8,
                                                void *);
static int zfcp_erp_port_reopen_internal(struct zfcp_port *, int, u8, void *);
static int zfcp_erp_unit_reopen_internal(struct zfcp_unit *, int, u8, void *);

static int zfcp_erp_port_reopen_all_internal(struct zfcp_adapter *, int, u8,
                                             void *);
static int zfcp_erp_unit_reopen_all_internal(struct zfcp_port *, int, u8,
                                             void *);

static void zfcp_erp_adapter_block(struct zfcp_adapter *, int);
static void zfcp_erp_adapter_unblock(struct zfcp_adapter *);
static void zfcp_erp_port_block(struct zfcp_port *, int);
static void zfcp_erp_port_unblock(struct zfcp_port *);
static void zfcp_erp_unit_block(struct zfcp_unit *, int);
static void zfcp_erp_unit_unblock(struct zfcp_unit *);

static int zfcp_erp_thread(void *);

static int zfcp_erp_strategy(struct zfcp_erp_action *);

static int zfcp_erp_strategy_do_action(struct zfcp_erp_action *);
static int zfcp_erp_strategy_memwait(struct zfcp_erp_action *);
static int zfcp_erp_strategy_check_target(struct zfcp_erp_action *, int);
static int zfcp_erp_strategy_check_unit(struct zfcp_unit *, int);
static int zfcp_erp_strategy_check_port(struct zfcp_port *, int);
static int zfcp_erp_strategy_check_adapter(struct zfcp_adapter *, int);
static int zfcp_erp_strategy_statechange(int, u32, struct zfcp_adapter *,
                                         struct zfcp_port *,
                                         struct zfcp_unit *, int);
static int zfcp_erp_strategy_statechange_detected(atomic_t *, u32);
static int zfcp_erp_strategy_followup_actions(int, struct zfcp_adapter *,
                                              struct zfcp_port *,
                                              struct zfcp_unit *, int);
static int zfcp_erp_strategy_check_queues(struct zfcp_adapter *);
static int zfcp_erp_strategy_check_action(struct zfcp_erp_action *, int);

static int zfcp_erp_adapter_strategy(struct zfcp_erp_action *);
static int zfcp_erp_adapter_strategy_generic(struct zfcp_erp_action *, int);
static int zfcp_erp_adapter_strategy_close(struct zfcp_erp_action *);
static int zfcp_erp_adapter_strategy_open(struct zfcp_erp_action *);
static int zfcp_erp_adapter_strategy_open_qdio(struct zfcp_erp_action *);
static int zfcp_erp_adapter_strategy_open_fsf(struct zfcp_erp_action *);
static int zfcp_erp_adapter_strategy_open_fsf_xconfig(struct zfcp_erp_action *);
static int zfcp_erp_adapter_strategy_open_fsf_xport(struct zfcp_erp_action *);
static int zfcp_erp_adapter_strategy_open_fsf_statusread(
        struct zfcp_erp_action *);

static int zfcp_erp_port_forced_strategy(struct zfcp_erp_action *);
static int zfcp_erp_port_forced_strategy_close(struct zfcp_erp_action *);

static int zfcp_erp_port_strategy(struct zfcp_erp_action *);
static int zfcp_erp_port_strategy_clearstati(struct zfcp_port *);
static int zfcp_erp_port_strategy_close(struct zfcp_erp_action *);
static int zfcp_erp_port_strategy_open(struct zfcp_erp_action *);
static int zfcp_erp_port_strategy_open_nameserver(struct zfcp_erp_action *);
static int zfcp_erp_port_strategy_open_nameserver_wakeup(
        struct zfcp_erp_action *);
static int zfcp_erp_port_strategy_open_common(struct zfcp_erp_action *);
static int zfcp_erp_port_strategy_open_common_lookup(struct zfcp_erp_action *);
static int zfcp_erp_port_strategy_open_port(struct zfcp_erp_action *);

static int zfcp_erp_unit_strategy(struct zfcp_erp_action *);
static int zfcp_erp_unit_strategy_clearstati(struct zfcp_unit *);
static int zfcp_erp_unit_strategy_close(struct zfcp_erp_action *);
static int zfcp_erp_unit_strategy_open(struct zfcp_erp_action *);

static void zfcp_erp_action_dismiss_adapter(struct zfcp_adapter *);
static void zfcp_erp_action_dismiss_port(struct zfcp_port *);
static void zfcp_erp_action_dismiss_unit(struct zfcp_unit *);
static void zfcp_erp_action_dismiss(struct zfcp_erp_action *);

static int zfcp_erp_action_enqueue(int, struct zfcp_adapter *,
                                   struct zfcp_port *, struct zfcp_unit *,
                                   u8 id, void *ref);
static int zfcp_erp_action_dequeue(struct zfcp_erp_action *);
static void zfcp_erp_action_cleanup(int, struct zfcp_adapter *,
                                    struct zfcp_port *, struct zfcp_unit *,
                                    int);

static void zfcp_erp_action_ready(struct zfcp_erp_action *);
static int  zfcp_erp_action_exists(struct zfcp_erp_action *);

static void zfcp_erp_action_to_ready(struct zfcp_erp_action *);
static void zfcp_erp_action_to_running(struct zfcp_erp_action *);

static void zfcp_erp_memwait_handler(unsigned long);

/**
 * zfcp_close_qdio - close qdio queues for an adapter
 */
static void zfcp_close_qdio(struct zfcp_adapter *adapter)
{
        struct zfcp_qdio_queue *req_queue;
        int first, count;

        if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status))
                return;

        /* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
        req_queue = &adapter->request_queue;
        write_lock_irq(&req_queue->queue_lock);
        atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
        write_unlock_irq(&req_queue->queue_lock);

        while (qdio_shutdown(adapter->ccw_device,
                             QDIO_FLAG_CLEANUP_USING_CLEAR) == -EINPROGRESS)
                ssleep(1);

        /* cleanup used outbound sbals */
        count = atomic_read(&req_queue->free_count);
        if (count < QDIO_MAX_BUFFERS_PER_Q) {
                first = (req_queue->free_index+count) % QDIO_MAX_BUFFERS_PER_Q;
                count = QDIO_MAX_BUFFERS_PER_Q - count;
                zfcp_qdio_zero_sbals(req_queue->buffer, first, count);
        }
        req_queue->free_index = 0;
        atomic_set(&req_queue->free_count, 0);
        req_queue->distance_from_int = 0;
        adapter->response_queue.free_index = 0;
        atomic_set(&adapter->response_queue.free_count, 0);
}

/**
 * zfcp_close_fsf - stop FSF operations for an adapter
 *
 * Dismiss and cleanup all pending fsf_reqs (this wakes up all initiators of
 * requests waiting for completion; especially this returns SCSI commands
 * with error state).
 */
static void zfcp_close_fsf(struct zfcp_adapter *adapter)
{
        /* close queues to ensure that buffers are not accessed by adapter */
        zfcp_close_qdio(adapter);
        zfcp_fsf_req_dismiss_all(adapter);
        /* reset FSF request sequence number */
        adapter->fsf_req_seq_no = 0;
        /* all ports and units are closed */
        zfcp_erp_modify_adapter_status(adapter, 24, NULL,
                                       ZFCP_STATUS_COMMON_OPEN, ZFCP_CLEAR);
}

/**
 * zfcp_fsf_request_timeout_handler - called if a request timed out
 * @data: pointer to adapter for handler function
 *
 * This function needs to be called if requests (ELS, Generic Service,
 * or SCSI commands) exceed a certain time limit. The assumption is
 * that after the time limit the adapter get stuck. So we trigger a reopen of
 * the adapter.
 */
static void zfcp_fsf_request_timeout_handler(unsigned long data)
{
        struct zfcp_adapter *adapter = (struct zfcp_adapter *) data;
        zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED, 62,
                                NULL);
}

void zfcp_fsf_start_timer(struct zfcp_fsf_req *fsf_req, unsigned long timeout)
{
        fsf_req->timer.function = zfcp_fsf_request_timeout_handler;
        fsf_req->timer.data = (unsigned long) fsf_req->adapter;
        fsf_req->timer.expires = jiffies + timeout;
        add_timer(&fsf_req->timer);
}

/*
 * function:
 *
 * purpose:     called if an adapter failed,
 *              initiates adapter recovery which is done
 *              asynchronously
 *
 * returns:     0       - initiated action successfully
 *              <0      - failed to initiate action
 */
static int zfcp_erp_adapter_reopen_internal(struct zfcp_adapter *adapter,
                                            int clear_mask, u8 id, void *ref)
{
        int retval;

        ZFCP_LOG_DEBUG("reopen adapter %s\n",
                       zfcp_get_busid_by_adapter(adapter));

        zfcp_erp_adapter_block(adapter, clear_mask);

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_FAILED, &adapter->status)) {
                ZFCP_LOG_DEBUG("skipped reopen of failed adapter %s\n",
                               zfcp_get_busid_by_adapter(adapter));
                /* ensure propagation of failed status to new devices */
                zfcp_erp_adapter_failed(adapter, 13, NULL);
                retval = -EIO;
                goto out;
        }
        retval = zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_ADAPTER,
                                         adapter, NULL, NULL, id, ref);

 out:
        return retval;
}

/*
 * function:
 *
 * purpose:     Wrappper for zfcp_erp_adapter_reopen_internal
 *              used to ensure the correct locking
 *
 * returns:     0       - initiated action successfully
 *              <0      - failed to initiate action
 */
int zfcp_erp_adapter_reopen(struct zfcp_adapter *adapter, int clear_mask,
                            u8 id, void *ref)
{
        int retval;
        unsigned long flags;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);
        retval = zfcp_erp_adapter_reopen_internal(adapter, clear_mask, id, ref);
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);

        return retval;
}

int zfcp_erp_adapter_shutdown(struct zfcp_adapter *adapter, int clear_mask,
                              u8 id, void *ref)
{
        int retval;

        retval = zfcp_erp_adapter_reopen(adapter,
                                         ZFCP_STATUS_COMMON_RUNNING |
                                         ZFCP_STATUS_COMMON_ERP_FAILED |
                                         clear_mask, id, ref);

        return retval;
}

int zfcp_erp_port_shutdown(struct zfcp_port *port, int clear_mask, u8 id,
                           void *ref)
{
        int retval;

        retval = zfcp_erp_port_reopen(port,
                                      ZFCP_STATUS_COMMON_RUNNING |
                                      ZFCP_STATUS_COMMON_ERP_FAILED |
                                      clear_mask, id, ref);

        return retval;
}

int zfcp_erp_unit_shutdown(struct zfcp_unit *unit, int clear_mask, u8 id,
                           void *ref)
{
        int retval;

        retval = zfcp_erp_unit_reopen(unit,
                                      ZFCP_STATUS_COMMON_RUNNING |
                                      ZFCP_STATUS_COMMON_ERP_FAILED |
                                      clear_mask, id, ref);

        return retval;
}


/**
 * zfcp_erp_adisc - send ADISC ELS command
 * @port: port structure
 */
static int
zfcp_erp_adisc(struct zfcp_port *port)
{
        struct zfcp_adapter *adapter = port->adapter;
        struct zfcp_send_els *send_els;
        struct zfcp_ls_adisc *adisc;
        void *address = NULL;
        int retval = 0;

        send_els = kzalloc(sizeof(struct zfcp_send_els), GFP_ATOMIC);
        if (send_els == NULL)
                goto nomem;

        send_els->req = kmalloc(sizeof(struct scatterlist), GFP_ATOMIC);
        if (send_els->req == NULL)
                goto nomem;
        sg_init_table(send_els->req, 1);

        send_els->resp = kmalloc(sizeof(struct scatterlist), GFP_ATOMIC);
        if (send_els->resp == NULL)
                goto nomem;
        sg_init_table(send_els->resp, 1);

        address = (void *) get_zeroed_page(GFP_ATOMIC);
        if (address == NULL)
                goto nomem;

        zfcp_address_to_sg(address, send_els->req, sizeof(struct zfcp_ls_adisc));
        address += PAGE_SIZE >> 1;
        zfcp_address_to_sg(address, send_els->resp, sizeof(struct zfcp_ls_adisc_acc));
        send_els->req_count = send_els->resp_count = 1;

        send_els->adapter = adapter;
        send_els->port = port;
        send_els->d_id = port->d_id;
        send_els->handler = zfcp_erp_adisc_handler;
        send_els->handler_data = (unsigned long) send_els;

        adisc = zfcp_sg_to_address(send_els->req);
        send_els->ls_code = adisc->code = ZFCP_LS_ADISC;

        /* acc. to FC-FS, hard_nport_id in ADISC should not be set for ports
           without FC-AL-2 capability, so we don't set it */
        adisc->wwpn = fc_host_port_name(adapter->scsi_host);
        adisc->wwnn = fc_host_node_name(adapter->scsi_host);
        adisc->nport_id = fc_host_port_id(adapter->scsi_host);
        ZFCP_LOG_INFO("ADISC request from s_id 0x%06x to d_id 0x%06x "
                      "(wwpn=0x%016Lx, wwnn=0x%016Lx, "
                      "hard_nport_id=0x%06x, nport_id=0x%06x)\n",
                      adisc->nport_id, send_els->d_id, (wwn_t) adisc->wwpn,
                      (wwn_t) adisc->wwnn, adisc->hard_nport_id,
                      adisc->nport_id);

        retval = zfcp_fsf_send_els(send_els);
        if (retval != 0) {
                ZFCP_LOG_NORMAL("error: initiation of Send ELS failed for port "
                                "0x%06x on adapter %s\n", send_els->d_id,
                                zfcp_get_busid_by_adapter(adapter));
                goto freemem;
        }

        goto out;

 nomem:
        retval = -ENOMEM;
 freemem:
        if (address != NULL)
                __free_pages(sg_page(send_els->req), 0);
        if (send_els != NULL) {
                kfree(send_els->req);
                kfree(send_els->resp);
                kfree(send_els);
        }
 out:
        return retval;
}


/**
 * zfcp_erp_adisc_handler - handler for ADISC ELS command
 * @data: pointer to struct zfcp_send_els
 *
 * If ADISC failed (LS_RJT or timed out) forced reopen of the port is triggered.
 */
static void
zfcp_erp_adisc_handler(unsigned long data)
{
        struct zfcp_send_els *send_els;
        struct zfcp_port *port;
        struct zfcp_adapter *adapter;
        u32 d_id;
        struct zfcp_ls_adisc_acc *adisc;

        send_els = (struct zfcp_send_els *) data;
        adapter = send_els->adapter;
        port = send_els->port;
        d_id = send_els->d_id;

        /* request rejected or timed out */
        if (send_els->status != 0) {
                ZFCP_LOG_NORMAL("ELS request rejected/timed out, "
                                "force physical port reopen "
                                "(adapter %s, port d_id=0x%06x)\n",
                                zfcp_get_busid_by_adapter(adapter), d_id);
                if (zfcp_erp_port_forced_reopen(port, 0, 63, NULL))
                        ZFCP_LOG_NORMAL("failed reopen of port "
                                        "(adapter %s, wwpn=0x%016Lx)\n",
                                        zfcp_get_busid_by_port(port),
                                        port->wwpn);
                goto out;
        }

        adisc = zfcp_sg_to_address(send_els->resp);

        ZFCP_LOG_INFO("ADISC response from d_id 0x%06x to s_id "
                      "0x%06x (wwpn=0x%016Lx, wwnn=0x%016Lx, "
                      "hard_nport_id=0x%06x, nport_id=0x%06x)\n",
                      d_id, fc_host_port_id(adapter->scsi_host),
                      (wwn_t) adisc->wwpn, (wwn_t) adisc->wwnn,
                      adisc->hard_nport_id, adisc->nport_id);

        /* set wwnn for port */
        if (port->wwnn == 0)
                port->wwnn = adisc->wwnn;

        if (port->wwpn != adisc->wwpn) {
                ZFCP_LOG_NORMAL("d_id assignment changed, reopening "
                                "port (adapter %s, wwpn=0x%016Lx, "
                                "adisc_resp_wwpn=0x%016Lx)\n",
                                zfcp_get_busid_by_port(port),
                                port->wwpn, (wwn_t) adisc->wwpn);
                if (zfcp_erp_port_reopen(port, 0, 64, NULL))
                        ZFCP_LOG_NORMAL("failed reopen of port "
                                        "(adapter %s, wwpn=0x%016Lx)\n",
                                        zfcp_get_busid_by_port(port),
                                        port->wwpn);
        }

 out:
        zfcp_port_put(port);
        __free_pages(sg_page(send_els->req), 0);
        kfree(send_els->req);
        kfree(send_els->resp);
        kfree(send_els);
}


/**
 * zfcp_test_link - lightweight link test procedure
 * @port: port to be tested
 *
 * Test status of a link to a remote port using the ELS command ADISC.
 */
int
zfcp_test_link(struct zfcp_port *port)
{
        int retval;

        zfcp_port_get(port);
        retval = zfcp_erp_adisc(port);
        if (retval != 0 && retval != -EBUSY) {
                zfcp_port_put(port);
                ZFCP_LOG_NORMAL("reopen needed for port 0x%016Lx "
                                "on adapter %s\n ", port->wwpn,
                                zfcp_get_busid_by_port(port));
                retval = zfcp_erp_port_forced_reopen(port, 0, 65, NULL);
                if (retval != 0) {
                        ZFCP_LOG_NORMAL("reopen of remote port 0x%016Lx "
                                        "on adapter %s failed\n", port->wwpn,
                                        zfcp_get_busid_by_port(port));
                        retval = -EPERM;
                }
        }

        return retval;
}


/*
 * function:
 *
 * purpose:     called if a port failed to be opened normally
 *              initiates Forced Reopen recovery which is done
 *              asynchronously
 *
 * returns:     0       - initiated action successfully
 *              <0      - failed to initiate action
 */
static int zfcp_erp_port_forced_reopen_internal(struct zfcp_port *port,
                                                int clear_mask, u8 id,
                                                void *ref)
{
        int retval;

        ZFCP_LOG_DEBUG("forced reopen of port 0x%016Lx on adapter %s\n",
                       port->wwpn, zfcp_get_busid_by_port(port));

        zfcp_erp_port_block(port, clear_mask);

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_FAILED, &port->status)) {
                ZFCP_LOG_DEBUG("skipped forced reopen of failed port 0x%016Lx "
                               "on adapter %s\n", port->wwpn,
                               zfcp_get_busid_by_port(port));
                retval = -EIO;
                goto out;
        }

        retval = zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_PORT_FORCED,
                                         port->adapter, port, NULL, id, ref);

 out:
        return retval;
}

/*
 * function:
 *
 * purpose:     Wrappper for zfcp_erp_port_forced_reopen_internal
 *              used to ensure the correct locking
 *
 * returns:     0       - initiated action successfully
 *              <0      - failed to initiate action
 */
int zfcp_erp_port_forced_reopen(struct zfcp_port *port, int clear_mask, u8 id,
                                void *ref)
{
        int retval;
        unsigned long flags;
        struct zfcp_adapter *adapter;

        adapter = port->adapter;
        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);
        retval = zfcp_erp_port_forced_reopen_internal(port, clear_mask, id,
                                                      ref);
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);

        return retval;
}

/*
 * function:
 *
 * purpose:     called if a port is to be opened
 *              initiates Reopen recovery which is done
 *              asynchronously
 *
 * returns:     0       - initiated action successfully
 *              <0      - failed to initiate action
 */
static int zfcp_erp_port_reopen_internal(struct zfcp_port *port, int clear_mask,
                                         u8 id, void *ref)
{
        int retval;

        ZFCP_LOG_DEBUG("reopen of port 0x%016Lx on adapter %s\n",
                       port->wwpn, zfcp_get_busid_by_port(port));

        zfcp_erp_port_block(port, clear_mask);

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_FAILED, &port->status)) {
                ZFCP_LOG_DEBUG("skipped reopen of failed port 0x%016Lx "
                               "on adapter %s\n", port->wwpn,
                               zfcp_get_busid_by_port(port));
                /* ensure propagation of failed status to new devices */
                zfcp_erp_port_failed(port, 14, NULL);
                retval = -EIO;
                goto out;
        }

        retval = zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_PORT,
                                         port->adapter, port, NULL, id, ref);

 out:
        return retval;
}

/**
 * zfcp_erp_port_reopen - initiate reopen of a remote port
 * @port: port to be reopened
 * @clear_mask: specifies flags in port status to be cleared
 * Return: 0 on success, < 0 on error
 *
 * This is a wrappper function for zfcp_erp_port_reopen_internal. It ensures
 * correct locking. An error recovery task is initiated to do the reopen.
 * To wait for the completion of the reopen zfcp_erp_wait should be used.
 */
int zfcp_erp_port_reopen(struct zfcp_port *port, int clear_mask, u8 id,
                         void *ref)
{
        int retval;
        unsigned long flags;
        struct zfcp_adapter *adapter = port->adapter;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);
        retval = zfcp_erp_port_reopen_internal(port, clear_mask, id, ref);
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);

        return retval;
}

/*
 * function:
 *
 * purpose:     called if a unit is to be opened
 *              initiates Reopen recovery which is done
 *              asynchronously
 *
 * returns:     0       - initiated action successfully
 *              <0      - failed to initiate action
 */
static int zfcp_erp_unit_reopen_internal(struct zfcp_unit *unit, int clear_mask,
                                         u8 id, void *ref)
{
        int retval;
        struct zfcp_adapter *adapter = unit->port->adapter;

        ZFCP_LOG_DEBUG("reopen of unit 0x%016Lx on port 0x%016Lx "
                       "on adapter %s\n", unit->fcp_lun,
                       unit->port->wwpn, zfcp_get_busid_by_unit(unit));

        zfcp_erp_unit_block(unit, clear_mask);

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_FAILED, &unit->status)) {
                ZFCP_LOG_DEBUG("skipped reopen of failed unit 0x%016Lx "
                               "on port 0x%016Lx on adapter %s\n",
                               unit->fcp_lun, unit->port->wwpn,
                               zfcp_get_busid_by_unit(unit));
                retval = -EIO;
                goto out;
        }

        retval = zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_UNIT,
                                         adapter, unit->port, unit, id, ref);
 out:
        return retval;
}

/**
 * zfcp_erp_unit_reopen - initiate reopen of a unit
 * @unit: unit to be reopened
 * @clear_mask: specifies flags in unit status to be cleared
 * Return: 0 on success, < 0 on error
 *
 * This is a wrappper for zfcp_erp_unit_reopen_internal. It ensures correct
 * locking. An error recovery task is initiated to do the reopen.
 * To wait for the completion of the reopen zfcp_erp_wait should be used.
 */
int zfcp_erp_unit_reopen(struct zfcp_unit *unit, int clear_mask, u8 id,
                         void *ref)
{
        int retval;
        unsigned long flags;
        struct zfcp_adapter *adapter;
        struct zfcp_port *port;

        port = unit->port;
        adapter = port->adapter;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);
        retval = zfcp_erp_unit_reopen_internal(unit, clear_mask, id, ref);
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);

        return retval;
}

/**
 * zfcp_erp_adapter_block - mark adapter as blocked, block scsi requests
 */
static void zfcp_erp_adapter_block(struct zfcp_adapter *adapter, int clear_mask)
{
        zfcp_erp_modify_adapter_status(adapter, 15, NULL,
                                       ZFCP_STATUS_COMMON_UNBLOCKED |
                                       clear_mask, ZFCP_CLEAR);
}

/* FIXME: isn't really atomic */
/*
 * returns the mask which has not been set so far, i.e.
 * 0 if no bit has been changed, !0 if some bit has been changed
 */
static int atomic_test_and_set_mask(unsigned long mask, atomic_t *v)
{
        int changed_bits = (atomic_read(v) /*XOR*/^ mask) & mask;
        atomic_set_mask(mask, v);
        return changed_bits;
}

/* FIXME: isn't really atomic */
/*
 * returns the mask which has not been cleared so far, i.e.
 * 0 if no bit has been changed, !0 if some bit has been changed
 */
static int atomic_test_and_clear_mask(unsigned long mask, atomic_t *v)
{
        int changed_bits = atomic_read(v) & mask;
        atomic_clear_mask(mask, v);
        return changed_bits;
}

/**
 * zfcp_erp_adapter_unblock - mark adapter as unblocked, allow scsi requests
 */
static void zfcp_erp_adapter_unblock(struct zfcp_adapter *adapter)
{
        if (atomic_test_and_set_mask(ZFCP_STATUS_COMMON_UNBLOCKED,
                                     &adapter->status))
                zfcp_rec_dbf_event_adapter(16, NULL, adapter);
}

/*
 * function:
 *
 * purpose:     disable I/O,
 *              return any open requests and clean them up,
 *              aim: no pending and incoming I/O
 *
 * returns:
 */
static void
zfcp_erp_port_block(struct zfcp_port *port, int clear_mask)
{
        zfcp_erp_modify_port_status(port, 17, NULL,
                                    ZFCP_STATUS_COMMON_UNBLOCKED | clear_mask,
                                    ZFCP_CLEAR);
}

/*
 * function:
 *
 * purpose:     enable I/O
 *
 * returns:
 */
static void
zfcp_erp_port_unblock(struct zfcp_port *port)
{
        if (atomic_test_and_set_mask(ZFCP_STATUS_COMMON_UNBLOCKED,
                                     &port->status))
                zfcp_rec_dbf_event_port(18, NULL, port);
}

/*
 * function:
 *
 * purpose:     disable I/O,
 *              return any open requests and clean them up,
 *              aim: no pending and incoming I/O
 *
 * returns:
 */
static void
zfcp_erp_unit_block(struct zfcp_unit *unit, int clear_mask)
{
        zfcp_erp_modify_unit_status(unit, 19, NULL,
                                    ZFCP_STATUS_COMMON_UNBLOCKED | clear_mask,
                                    ZFCP_CLEAR);
}

/*
 * function:
 *
 * purpose:     enable I/O
 *
 * returns:
 */
static void
zfcp_erp_unit_unblock(struct zfcp_unit *unit)
{
        if (atomic_test_and_set_mask(ZFCP_STATUS_COMMON_UNBLOCKED,
                                     &unit->status))
                zfcp_rec_dbf_event_unit(20, NULL, unit);
}

static void
zfcp_erp_action_ready(struct zfcp_erp_action *erp_action)
{
        struct zfcp_adapter *adapter = erp_action->adapter;

        zfcp_erp_action_to_ready(erp_action);
        up(&adapter->erp_ready_sem);
        zfcp_rec_dbf_event_thread(2, adapter, 0);
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     <0                      erp_action not found in any list
 *              ZFCP_ERP_ACTION_READY   erp_action is in ready list
 *              ZFCP_ERP_ACTION_RUNNING erp_action is in running list
 *
 * locks:       erp_lock must be held
 */
static int
zfcp_erp_action_exists(struct zfcp_erp_action *erp_action)
{
        int retval = -EINVAL;
        struct list_head *entry;
        struct zfcp_erp_action *entry_erp_action;
        struct zfcp_adapter *adapter = erp_action->adapter;

        /* search in running list */
        list_for_each(entry, &adapter->erp_running_head) {
                entry_erp_action =
                    list_entry(entry, struct zfcp_erp_action, list);
                if (entry_erp_action == erp_action) {
                        retval = ZFCP_ERP_ACTION_RUNNING;
                        goto out;
                }
        }
        /* search in ready list */
        list_for_each(entry, &adapter->erp_ready_head) {
                entry_erp_action =
                    list_entry(entry, struct zfcp_erp_action, list);
                if (entry_erp_action == erp_action) {
                        retval = ZFCP_ERP_ACTION_READY;
                        goto out;
                }
        }

 out:
        return retval;
}

/*
 * purpose:     checks current status of action (timed out, dismissed, ...)
 *              and does appropriate preparations (dismiss fsf request, ...)
 *
 * locks:       called under erp_lock (disabled interrupts)
 */
static void
zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *erp_action)
{
        struct zfcp_adapter *adapter = erp_action->adapter;

        if (erp_action->fsf_req) {
                /* take lock to ensure that request is not deleted meanwhile */
                spin_lock(&adapter->req_list_lock);
                if (zfcp_reqlist_find_safe(adapter, erp_action->fsf_req) &&
                    erp_action->fsf_req->erp_action == erp_action) {
                        /* fsf_req still exists */
                        /* dismiss fsf_req of timed out/dismissed erp_action */
                        if (erp_action->status & (ZFCP_STATUS_ERP_DISMISSED |
                                                  ZFCP_STATUS_ERP_TIMEDOUT)) {
                                erp_action->fsf_req->status |=
                                        ZFCP_STATUS_FSFREQ_DISMISSED;
                                zfcp_rec_dbf_event_action(142, erp_action);
                        }
                        if (erp_action->status & ZFCP_STATUS_ERP_TIMEDOUT) {
                                zfcp_rec_dbf_event_action(143, erp_action);
                                ZFCP_LOG_NORMAL("error: erp step timed out "
                                                "(action=%d, fsf_req=%p)\n ",
                                                erp_action->action,
                                                erp_action->fsf_req);
                        }
                        /*
                         * If fsf_req is neither dismissed nor completed
                         * then keep it running asynchronously and don't mess
                         * with the association of erp_action and fsf_req.
                         */
                        if (erp_action->fsf_req->status &
                                        (ZFCP_STATUS_FSFREQ_COMPLETED |
                                               ZFCP_STATUS_FSFREQ_DISMISSED)) {
                                /* forget about association between fsf_req
                                   and erp_action */
                                erp_action->fsf_req = NULL;
                        }
                } else {
                        /*
                         * even if this fsf_req has gone, forget about
                         * association between erp_action and fsf_req
                         */
                        erp_action->fsf_req = NULL;
                }
                spin_unlock(&adapter->req_list_lock);
        }
}

/**
 * zfcp_erp_async_handler_nolock - complete erp_action
 *
 * Used for normal completion, time-out, dismissal and failure after
 * low memory condition.
 */
static void zfcp_erp_async_handler_nolock(struct zfcp_erp_action *erp_action,
                                          unsigned long set_mask)
{
        if (zfcp_erp_action_exists(erp_action) == ZFCP_ERP_ACTION_RUNNING) {
                erp_action->status |= set_mask;
                zfcp_erp_action_ready(erp_action);
        } else {
                /* action is ready or gone - nothing to do */
        }
}

/**
 * zfcp_erp_async_handler - wrapper for erp_async_handler_nolock w/ locking
 */
void zfcp_erp_async_handler(struct zfcp_erp_action *erp_action,
                            unsigned long set_mask)
{
        struct zfcp_adapter *adapter = erp_action->adapter;
        unsigned long flags;

        write_lock_irqsave(&adapter->erp_lock, flags);
        zfcp_erp_async_handler_nolock(erp_action, set_mask);
        write_unlock_irqrestore(&adapter->erp_lock, flags);
}

/*
 * purpose:     is called for erp_action which was slept waiting for
 *              memory becoming avaliable,
 *              will trigger that this action will be continued
 */
static void
zfcp_erp_memwait_handler(unsigned long data)
{
        struct zfcp_erp_action *erp_action = (struct zfcp_erp_action *) data;

        zfcp_erp_async_handler(erp_action, 0);
}

/*
 * purpose:     is called if an asynchronous erp step timed out,
 *              action gets an appropriate flag and will be processed
 *              accordingly
 */
static void zfcp_erp_timeout_handler(unsigned long data)
{
        struct zfcp_erp_action *erp_action = (struct zfcp_erp_action *) data;

        zfcp_erp_async_handler(erp_action, ZFCP_STATUS_ERP_TIMEDOUT);
}

/**
 * zfcp_erp_action_dismiss - dismiss an erp_action
 *
 * adapter->erp_lock must be held
 *
 * Dismissal of an erp_action is usually required if an erp_action of
 * higher priority is generated.
 */
static void zfcp_erp_action_dismiss(struct zfcp_erp_action *erp_action)
{
        erp_action->status |= ZFCP_STATUS_ERP_DISMISSED;
        if (zfcp_erp_action_exists(erp_action) == ZFCP_ERP_ACTION_RUNNING)
                zfcp_erp_action_ready(erp_action);
}

int
zfcp_erp_thread_setup(struct zfcp_adapter *adapter)
{
        int retval = 0;

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP, &adapter->status);

        retval = kernel_thread(zfcp_erp_thread, adapter, SIGCHLD);
        if (retval < 0) {
                ZFCP_LOG_NORMAL("error: creation of erp thread failed for "
                                "adapter %s\n",
                                zfcp_get_busid_by_adapter(adapter));
        } else {
                wait_event(adapter->erp_thread_wqh,
                           atomic_test_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP,
                                            &adapter->status));
        }

        return (retval < 0);
}

/*
 * function:
 *
 * purpose:
 *
 * returns:
 *
 * context:     process (i.e. proc-fs or rmmod/insmod)
 *
 * note:        The caller of this routine ensures that the specified
 *              adapter has been shut down and that this operation
 *              has been completed. Thus, there are no pending erp_actions
 *              which would need to be handled here.
 */
int
zfcp_erp_thread_kill(struct zfcp_adapter *adapter)
{
        int retval = 0;

        atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL, &adapter->status);
        up(&adapter->erp_ready_sem);
        zfcp_rec_dbf_event_thread(2, adapter, 1);

        wait_event(adapter->erp_thread_wqh,
                   !atomic_test_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP,
                                     &adapter->status));

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL,
                          &adapter->status);

        return retval;
}

/*
 * purpose:     is run as a kernel thread,
 *              goes through list of error recovery actions of associated adapter
 *              and delegates single action to execution
 *
 * returns:     0
 */
static int
zfcp_erp_thread(void *data)
{
        struct zfcp_adapter *adapter = (struct zfcp_adapter *) data;
        struct list_head *next;
        struct zfcp_erp_action *erp_action;
        unsigned long flags;

        daemonize("zfcperp%s", zfcp_get_busid_by_adapter(adapter));
        /* Block all signals */
        siginitsetinv(&current->blocked, 0);
        atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP, &adapter->status);
        wake_up(&adapter->erp_thread_wqh);

        while (!atomic_test_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL,
                                 &adapter->status)) {

                write_lock_irqsave(&adapter->erp_lock, flags);
                next = adapter->erp_ready_head.next;
                write_unlock_irqrestore(&adapter->erp_lock, flags);

                if (next != &adapter->erp_ready_head) {
                        erp_action =
                            list_entry(next, struct zfcp_erp_action, list);
                        /*
                         * process action (incl. [re]moving it
                         * from 'ready' queue)
                         */
                        zfcp_erp_strategy(erp_action);
                }

                /*
                 * sleep as long as there is nothing to do, i.e.
                 * no action in 'ready' queue to be processed and
                 * thread is not to be killed
                 */
                zfcp_rec_dbf_event_thread(4, adapter, 1);
                down_interruptible(&adapter->erp_ready_sem);
                zfcp_rec_dbf_event_thread(5, adapter, 1);
        }

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP, &adapter->status);
        wake_up(&adapter->erp_thread_wqh);

        return 0;
}

/*
 * function:
 *
 * purpose:     drives single error recovery action and schedules higher and
 *              subordinate actions, if necessary
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_SUCCEEDED      - action finished successfully (deqd)
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully (deqd)
 *              ZFCP_ERP_EXIT           - action finished (dequeued), offline
 *              ZFCP_ERP_DISMISSED      - action canceled (dequeued)
 */
static int
zfcp_erp_strategy(struct zfcp_erp_action *erp_action)
{
        int retval = 0;
        struct zfcp_adapter *adapter = erp_action->adapter;
        struct zfcp_port *port = erp_action->port;
        struct zfcp_unit *unit = erp_action->unit;
        int action = erp_action->action;
        u32 status = erp_action->status;
        unsigned long flags;

        /* serialise dismissing, timing out, moving, enqueueing */
        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);

        /* dequeue dismissed action and leave, if required */
        retval = zfcp_erp_strategy_check_action(erp_action, retval);
        if (retval == ZFCP_ERP_DISMISSED) {
                goto unlock;
        }

        /*
         * move action to 'running' queue before processing it
         * (to avoid a race condition regarding moving the
         * action to the 'running' queue and back)
         */
        zfcp_erp_action_to_running(erp_action);

        /*
         * try to process action as far as possible,
         * no lock to allow for blocking operations (kmalloc, qdio, ...),
         * afterwards the lock is required again for the following reasons:
         * - dequeueing of finished action and enqueueing of
         *   follow-up actions must be atomic so that any other
         *   reopen-routine does not believe there is nothing to do
         *   and that it is safe to enqueue something else,
         * - we want to force any control thread which is dismissing
         *   actions to finish this before we decide about
         *   necessary steps to be taken here further
         */
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
        retval = zfcp_erp_strategy_do_action(erp_action);
        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);

        /*
         * check for dismissed status again to avoid follow-up actions,
         * failing of targets and so on for dismissed actions,
         * we go through down() here because there has been an up()
         */
        if (erp_action->status & ZFCP_STATUS_ERP_DISMISSED)
                retval = ZFCP_ERP_CONTINUES;

        switch (retval) {
        case ZFCP_ERP_NOMEM:
                /* no memory to continue immediately, let it sleep */
                if (!(erp_action->status & ZFCP_STATUS_ERP_LOWMEM)) {
                        ++adapter->erp_low_mem_count;
                        erp_action->status |= ZFCP_STATUS_ERP_LOWMEM;
                }
                /* This condition is true if there is no memory available
                   for any erp_action on this adapter. This implies that there
                   are no elements in the memory pool(s) left for erp_actions.
                   This might happen if an erp_action that used a memory pool
                   element was timed out.
                 */
                if (adapter->erp_total_count == adapter->erp_low_mem_count) {
                        ZFCP_LOG_NORMAL("error: no mempool elements available, "
                                        "restarting I/O on adapter %s "
                                        "to free mempool\n",
                                        zfcp_get_busid_by_adapter(adapter));
                        zfcp_erp_adapter_reopen_internal(adapter, 0, 66, NULL);
                } else {
                retval = zfcp_erp_strategy_memwait(erp_action);
                }
                goto unlock;
        case ZFCP_ERP_CONTINUES:
                /* leave since this action runs asynchronously */
                if (erp_action->status & ZFCP_STATUS_ERP_LOWMEM) {
                        --adapter->erp_low_mem_count;
                        erp_action->status &= ~ZFCP_STATUS_ERP_LOWMEM;
                }
                goto unlock;
        }
        /* ok, finished action (whatever its result is) */

        /* check for unrecoverable targets */
        retval = zfcp_erp_strategy_check_target(erp_action, retval);

        /* action must be dequeued (here to allow for further ones) */
        zfcp_erp_action_dequeue(erp_action);

        /*
         * put this target through the erp mill again if someone has
         * requested to change the status of a target being online
         * to offline or the other way around
         * (old retval is preserved if nothing has to be done here)
         */
        retval = zfcp_erp_strategy_statechange(action, status, adapter,
                                               port, unit, retval);

        /*
         * leave if target is in permanent error state or if
         * action is repeated in order to process state change
         */
        if (retval == ZFCP_ERP_EXIT) {
                goto unlock;
        }

        /* trigger follow up actions */
        zfcp_erp_strategy_followup_actions(action, adapter, port, unit, retval);

 unlock:
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);

        if (retval != ZFCP_ERP_CONTINUES)
                zfcp_erp_action_cleanup(action, adapter, port, unit, retval);

        /*
         * a few tasks remain when the erp queues are empty
         * (don't do that if the last action evaluated was dismissed
         * since this clearly indicates that there is more to come) :
         * - close the name server port if it is open yet
         *   (enqueues another [probably] final action)
         * - otherwise, wake up whoever wants to be woken when we are
         *   done with erp
         */
        if (retval != ZFCP_ERP_DISMISSED)
                zfcp_erp_strategy_check_queues(adapter);

        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_DISMISSED      - if action has been dismissed
 *              retval                  - otherwise
 */
static int
zfcp_erp_strategy_check_action(struct zfcp_erp_action *erp_action, int retval)
{
        zfcp_erp_strategy_check_fsfreq(erp_action);

        if (erp_action->status & ZFCP_STATUS_ERP_DISMISSED) {
                zfcp_erp_action_dequeue(erp_action);
                retval = ZFCP_ERP_DISMISSED;
        }

        return retval;
}

static int
zfcp_erp_strategy_do_action(struct zfcp_erp_action *erp_action)
{
        int retval = ZFCP_ERP_FAILED;

        /*
         * try to execute/continue action as far as possible,
         * note: no lock in subsequent strategy routines
         * (this allows these routine to call schedule, e.g.
         * kmalloc with such flags or qdio_initialize & friends)
         * Note: in case of timeout, the separate strategies will fail
         * anyhow. No need for a special action. Even worse, a nameserver
         * failure would not wake up waiting ports without the call.
         */
        switch (erp_action->action) {

        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                retval = zfcp_erp_adapter_strategy(erp_action);
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
                retval = zfcp_erp_port_forced_strategy(erp_action);
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT:
                retval = zfcp_erp_port_strategy(erp_action);
                break;

        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                retval = zfcp_erp_unit_strategy(erp_action);
                break;

        default:
                ZFCP_LOG_NORMAL("bug: unknown erp action requested on "
                                "adapter %s (action=%d)\n",
                                zfcp_get_busid_by_adapter(erp_action->adapter),
                                erp_action->action);
        }

        return retval;
}

/*
 * function:
 *
 * purpose:     triggers retry of this action after a certain amount of time
 *              by means of timer provided by erp_action
 *
 * returns:     ZFCP_ERP_CONTINUES - erp_action sleeps in erp running queue
 */
static int
zfcp_erp_strategy_memwait(struct zfcp_erp_action *erp_action)
{
        int retval = ZFCP_ERP_CONTINUES;

        init_timer(&erp_action->timer);
        erp_action->timer.function = zfcp_erp_memwait_handler;
        erp_action->timer.data = (unsigned long) erp_action;
        erp_action->timer.expires = jiffies + ZFCP_ERP_MEMWAIT_TIMEOUT;
        add_timer(&erp_action->timer);

        return retval;
}

/*
 * function:    zfcp_erp_adapter_failed
 *
 * purpose:     sets the adapter and all underlying devices to ERP_FAILED
 *
 */
void
zfcp_erp_adapter_failed(struct zfcp_adapter *adapter, u8 id, void *ref)
{
        zfcp_erp_modify_adapter_status(adapter, id, ref,
                                       ZFCP_STATUS_COMMON_ERP_FAILED, ZFCP_SET);
        ZFCP_LOG_NORMAL("adapter erp failed on adapter %s\n",
                        zfcp_get_busid_by_adapter(adapter));
}

/*
 * function:    zfcp_erp_port_failed
 *
 * purpose:     sets the port and all underlying devices to ERP_FAILED
 *
 */
void
zfcp_erp_port_failed(struct zfcp_port *port, u8 id, void *ref)
{
        zfcp_erp_modify_port_status(port, id, ref,
                                    ZFCP_STATUS_COMMON_ERP_FAILED, ZFCP_SET);

        if (atomic_test_mask(ZFCP_STATUS_PORT_WKA, &port->status))
                ZFCP_LOG_NORMAL("port erp failed (adapter %s, "
                                "port d_id=0x%06x)\n",
                                zfcp_get_busid_by_port(port), port->d_id);
        else
                ZFCP_LOG_NORMAL("port erp failed (adapter %s, wwpn=0x%016Lx)\n",
                                zfcp_get_busid_by_port(port), port->wwpn);
}

/*
 * function:    zfcp_erp_unit_failed
 *
 * purpose:     sets the unit to ERP_FAILED
 *
 */
void
zfcp_erp_unit_failed(struct zfcp_unit *unit, u8 id, void *ref)
{
        zfcp_erp_modify_unit_status(unit, id, ref,
                                    ZFCP_STATUS_COMMON_ERP_FAILED, ZFCP_SET);

        ZFCP_LOG_NORMAL("unit erp failed on unit 0x%016Lx on port 0x%016Lx "
                        " on adapter %s\n", unit->fcp_lun,
                        unit->port->wwpn, zfcp_get_busid_by_unit(unit));
}

/*
 * function:    zfcp_erp_strategy_check_target
 *
 * purpose:     increments the erp action count on the device currently in
 *              recovery if the action failed or resets the count in case of
 *              success. If a maximum count is exceeded the device is marked
 *              as ERP_FAILED.
 *              The 'blocked' state of a target which has been recovered
 *              successfully is reset.
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (not considered)
 *              ZFCP_ERP_SUCCEEDED      - action finished successfully
 *              ZFCP_ERP_EXIT           - action failed and will not continue
 */
static int
zfcp_erp_strategy_check_target(struct zfcp_erp_action *erp_action, int result)
{
        struct zfcp_adapter *adapter = erp_action->adapter;
        struct zfcp_port *port = erp_action->port;
        struct zfcp_unit *unit = erp_action->unit;

        switch (erp_action->action) {

        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                result = zfcp_erp_strategy_check_unit(unit, result);
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
        case ZFCP_ERP_ACTION_REOPEN_PORT:
                result = zfcp_erp_strategy_check_port(port, result);
                break;

        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                result = zfcp_erp_strategy_check_adapter(adapter, result);
                break;
        }

        return result;
}

static int
zfcp_erp_strategy_statechange(int action,
                              u32 status,
                              struct zfcp_adapter *adapter,
                              struct zfcp_port *port,
                              struct zfcp_unit *unit, int retval)
{
        switch (action) {

        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                if (zfcp_erp_strategy_statechange_detected(&adapter->status,
                                                           status)) {
                        zfcp_erp_adapter_reopen_internal(adapter,
                                                ZFCP_STATUS_COMMON_ERP_FAILED,
                                                67, NULL);
                        retval = ZFCP_ERP_EXIT;
                }
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
        case ZFCP_ERP_ACTION_REOPEN_PORT:
                if (zfcp_erp_strategy_statechange_detected(&port->status,
                                                           status)) {
                        zfcp_erp_port_reopen_internal(port,
                                                ZFCP_STATUS_COMMON_ERP_FAILED,
                                                68, NULL);
                        retval = ZFCP_ERP_EXIT;
                }
                break;

        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                if (zfcp_erp_strategy_statechange_detected(&unit->status,
                                                           status)) {
                        zfcp_erp_unit_reopen_internal(unit,
                                                ZFCP_STATUS_COMMON_ERP_FAILED,
                                                69, NULL);
                        retval = ZFCP_ERP_EXIT;
                }
                break;
        }

        return retval;
}

static int
zfcp_erp_strategy_statechange_detected(atomic_t * target_status, u32 erp_status)
{
        return
            /* take it online */
            (atomic_test_mask(ZFCP_STATUS_COMMON_RUNNING, target_status) &&
             (ZFCP_STATUS_ERP_CLOSE_ONLY & erp_status)) ||
            /* take it offline */
            (!atomic_test_mask(ZFCP_STATUS_COMMON_RUNNING, target_status) &&
             !(ZFCP_STATUS_ERP_CLOSE_ONLY & erp_status));
}

static int
zfcp_erp_strategy_check_unit(struct zfcp_unit *unit, int result)
{
        switch (result) {
        case ZFCP_ERP_SUCCEEDED :
                atomic_set(&unit->erp_counter, 0);
                zfcp_erp_unit_unblock(unit);
                break;
        case ZFCP_ERP_FAILED :
                atomic_inc(&unit->erp_counter);
                if (atomic_read(&unit->erp_counter) > ZFCP_MAX_ERPS)
                        zfcp_erp_unit_failed(unit, 21, NULL);
                break;
        case ZFCP_ERP_EXIT :
                /* nothing */
                break;
        }

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_FAILED, &unit->status)) {
                zfcp_erp_unit_block(unit, 0); /* for ZFCP_ERP_SUCCEEDED */
                result = ZFCP_ERP_EXIT;
        }

        return result;
}

static int
zfcp_erp_strategy_check_port(struct zfcp_port *port, int result)
{
        switch (result) {
        case ZFCP_ERP_SUCCEEDED :
                atomic_set(&port->erp_counter, 0);
                zfcp_erp_port_unblock(port);
                break;
        case ZFCP_ERP_FAILED :
                atomic_inc(&port->erp_counter);
                if (atomic_read(&port->erp_counter) > ZFCP_MAX_ERPS)
                        zfcp_erp_port_failed(port, 22, NULL);
                break;
        case ZFCP_ERP_EXIT :
                /* nothing */
                break;
        }

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_FAILED, &port->status)) {
                zfcp_erp_port_block(port, 0); /* for ZFCP_ERP_SUCCEEDED */
                result = ZFCP_ERP_EXIT;
        }

        return result;
}

static int
zfcp_erp_strategy_check_adapter(struct zfcp_adapter *adapter, int result)
{
        switch (result) {
        case ZFCP_ERP_SUCCEEDED :
                atomic_set(&adapter->erp_counter, 0);
                zfcp_erp_adapter_unblock(adapter);
                break;
        case ZFCP_ERP_FAILED :
                atomic_inc(&adapter->erp_counter);
                if (atomic_read(&adapter->erp_counter) > ZFCP_MAX_ERPS)
                        zfcp_erp_adapter_failed(adapter, 23, NULL);
                break;
        case ZFCP_ERP_EXIT :
                /* nothing */
                break;
        }

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_FAILED, &adapter->status)) {
                zfcp_erp_adapter_block(adapter, 0); /* for ZFCP_ERP_SUCCEEDED */
                result = ZFCP_ERP_EXIT;
        }

        return result;
}

struct zfcp_erp_add_work {
        struct zfcp_unit  *unit;
        struct work_struct work;
};

/**
 * zfcp_erp_scsi_scan
 * @data: pointer to a struct zfcp_erp_add_work
 *
 * Registers a logical unit with the SCSI stack.
 */
static void zfcp_erp_scsi_scan(struct work_struct *work)
{
        struct zfcp_erp_add_work *p =
                container_of(work, struct zfcp_erp_add_work, work);
        struct zfcp_unit *unit = p->unit;
        struct fc_rport *rport = unit->port->rport;
        scsi_scan_target(&rport->dev, 0, rport->scsi_target_id,
                         unit->scsi_lun, 0);
        atomic_clear_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING, &unit->status);
        zfcp_unit_put(unit);
        kfree(p);
}

/**
 * zfcp_erp_schedule_work
 * @unit: pointer to unit which should be registered with SCSI stack
 *
 * Schedules work which registers a unit with the SCSI stack
 */
static void
zfcp_erp_schedule_work(struct zfcp_unit *unit)
{
        struct zfcp_erp_add_work *p;

        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (!p) {
                ZFCP_LOG_NORMAL("error: Out of resources. Could not register "
                                "the FCP-LUN 0x%Lx connected to "
                                "the port with WWPN 0x%Lx connected to "
                                "the adapter %s with the SCSI stack.\n",
                                unit->fcp_lun,
                                unit->port->wwpn,
                                zfcp_get_busid_by_unit(unit));
                return;
        }

        zfcp_unit_get(unit);
        atomic_set_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING, &unit->status);
        INIT_WORK(&p->work, zfcp_erp_scsi_scan);
        p->unit = unit;
        schedule_work(&p->work);
}

/*
 * function:
 *
 * purpose:     remaining things in good cases,
 *              escalation in bad cases
 *
 * returns:
 */
static int
zfcp_erp_strategy_followup_actions(int action,
                                   struct zfcp_adapter *adapter,
                                   struct zfcp_port *port,
                                   struct zfcp_unit *unit, int status)
{
        /* initiate follow-up actions depending on success of finished action */
        switch (action) {

        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                if (status == ZFCP_ERP_SUCCEEDED)
                        zfcp_erp_port_reopen_all_internal(adapter, 0, 70, NULL);
                else
                        zfcp_erp_adapter_reopen_internal(adapter, 0, 71, NULL);
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
                if (status == ZFCP_ERP_SUCCEEDED)
                        zfcp_erp_port_reopen_internal(port, 0, 72, NULL);
                else
                        zfcp_erp_adapter_reopen_internal(adapter, 0, 73, NULL);
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT:
                if (status == ZFCP_ERP_SUCCEEDED)
                        zfcp_erp_unit_reopen_all_internal(port, 0, 74, NULL);
                else
                        zfcp_erp_port_forced_reopen_internal(port, 0, 75, NULL);
                break;

        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                /* Nothing to do if status == ZFCP_ERP_SUCCEEDED */
                if (status != ZFCP_ERP_SUCCEEDED)
                        zfcp_erp_port_reopen_internal(unit->port, 0, 76, NULL);
                break;
        }

        return 0;
}

static int
zfcp_erp_strategy_check_queues(struct zfcp_adapter *adapter)
{
        unsigned long flags;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        read_lock(&adapter->erp_lock);
        if (list_empty(&adapter->erp_ready_head) &&
            list_empty(&adapter->erp_running_head)) {
                        atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_PENDING,
                                          &adapter->status);
                        wake_up(&adapter->erp_done_wqh);
        }
        read_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);

        return 0;
}

/**
 * zfcp_erp_wait - wait for completion of error recovery on an adapter
 * @adapter: adapter for which to wait for completion of its error recovery
 * Return: 0
 */
int
zfcp_erp_wait(struct zfcp_adapter *adapter)
{
        int retval = 0;

        wait_event(adapter->erp_done_wqh,
                   !atomic_test_mask(ZFCP_STATUS_ADAPTER_ERP_PENDING,
                                     &adapter->status));

        return retval;
}

void zfcp_erp_modify_adapter_status(struct zfcp_adapter *adapter, u8 id,
                                    void *ref, u32 mask, int set_or_clear)
{
        struct zfcp_port *port;
        u32 changed, common_mask = mask & ZFCP_COMMON_FLAGS;

        if (set_or_clear == ZFCP_SET) {
                changed = atomic_test_and_set_mask(mask, &adapter->status);
        } else {
                changed = atomic_test_and_clear_mask(mask, &adapter->status);
                if (mask & ZFCP_STATUS_COMMON_ERP_FAILED)
                        atomic_set(&adapter->erp_counter, 0);
        }
        if (changed)
                zfcp_rec_dbf_event_adapter(id, ref, adapter);

        /* Deal with all underlying devices, only pass common_mask */
        if (common_mask)
                list_for_each_entry(port, &adapter->port_list_head, list)
                        zfcp_erp_modify_port_status(port, id, ref, common_mask,
                                                    set_or_clear);
}

/*
 * function:    zfcp_erp_modify_port_status
 *
 * purpose:     sets the port and all underlying devices to ERP_FAILED
 *
 */
void zfcp_erp_modify_port_status(struct zfcp_port *port, u8 id, void *ref,
                                 u32 mask, int set_or_clear)
{
        struct zfcp_unit *unit;
        u32 changed, common_mask = mask & ZFCP_COMMON_FLAGS;

        if (set_or_clear == ZFCP_SET) {
                changed = atomic_test_and_set_mask(mask, &port->status);
        } else {
                changed = atomic_test_and_clear_mask(mask, &port->status);
                if (mask & ZFCP_STATUS_COMMON_ERP_FAILED)
                        atomic_set(&port->erp_counter, 0);
        }
        if (changed)
                zfcp_rec_dbf_event_port(id, ref, port);

        /* Modify status of all underlying devices, only pass common mask */
        if (common_mask)
                list_for_each_entry(unit, &port->unit_list_head, list)
                        zfcp_erp_modify_unit_status(unit, id, ref, common_mask,
                                                    set_or_clear);
}

/*
 * function:    zfcp_erp_modify_unit_status
 *
 * purpose:     sets the unit to ERP_FAILED
 *
 */
void zfcp_erp_modify_unit_status(struct zfcp_unit *unit, u8 id, void *ref,
                                 u32 mask, int set_or_clear)
{
        u32 changed;

        if (set_or_clear == ZFCP_SET) {
                changed = atomic_test_and_set_mask(mask, &unit->status);
        } else {
                changed = atomic_test_and_clear_mask(mask, &unit->status);
                if (mask & ZFCP_STATUS_COMMON_ERP_FAILED) {
                        atomic_set(&unit->erp_counter, 0);
                }
        }
        if (changed)
                zfcp_rec_dbf_event_unit(id, ref, unit);
}

/*
 * function:
 *
 * purpose:     Wrappper for zfcp_erp_port_reopen_all_internal
 *              used to ensure the correct locking
 *
 * returns:     0       - initiated action successfully
 *              <0      - failed to initiate action
 */
int zfcp_erp_port_reopen_all(struct zfcp_adapter *adapter, int clear_mask,
                             u8 id, void *ref)
{
        int retval;
        unsigned long flags;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);
        retval = zfcp_erp_port_reopen_all_internal(adapter, clear_mask, id,
                                                   ref);
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);

        return retval;
}

static int zfcp_erp_port_reopen_all_internal(struct zfcp_adapter *adapter,
                                             int clear_mask, u8 id, void *ref)
{
        int retval = 0;
        struct zfcp_port *port;

        list_for_each_entry(port, &adapter->port_list_head, list)
                if (!atomic_test_mask(ZFCP_STATUS_PORT_WKA, &port->status))
                        zfcp_erp_port_reopen_internal(port, clear_mask, id,
                                                      ref);

        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     FIXME
 */
static int zfcp_erp_unit_reopen_all_internal(struct zfcp_port *port,
                                             int clear_mask, u8 id, void *ref)
{
        int retval = 0;
        struct zfcp_unit *unit;

        list_for_each_entry(unit, &port->unit_list_head, list)
                zfcp_erp_unit_reopen_internal(unit, clear_mask, id, ref);

        return retval;
}

/*
 * function:
 *
 * purpose:     this routine executes the 'Reopen Adapter' action
 *              (the entire action is processed synchronously, since
 *              there are no actions which might be run concurrently
 *              per definition)
 *
 * returns:     ZFCP_ERP_SUCCEEDED      - action finished successfully
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_adapter_strategy(struct zfcp_erp_action *erp_action)
{
        int retval;
        struct zfcp_adapter *adapter = erp_action->adapter;

        retval = zfcp_erp_adapter_strategy_close(erp_action);
        if (erp_action->status & ZFCP_STATUS_ERP_CLOSE_ONLY)
                retval = ZFCP_ERP_EXIT;
        else
                retval = zfcp_erp_adapter_strategy_open(erp_action);

        if (retval == ZFCP_ERP_FAILED) {
                ZFCP_LOG_INFO("Waiting to allow the adapter %s "
                              "to recover itself\n",
                              zfcp_get_busid_by_adapter(adapter));
                ssleep(ZFCP_TYPE2_RECOVERY_TIME);
        }

        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_SUCCEEDED      - action finished successfully
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_adapter_strategy_close(struct zfcp_erp_action *erp_action)
{
        int retval;

        atomic_set_mask(ZFCP_STATUS_COMMON_CLOSING,
                        &erp_action->adapter->status);
        retval = zfcp_erp_adapter_strategy_generic(erp_action, 1);
        atomic_clear_mask(ZFCP_STATUS_COMMON_CLOSING,
                          &erp_action->adapter->status);

        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_SUCCEEDED      - action finished successfully
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_adapter_strategy_open(struct zfcp_erp_action *erp_action)
{
        int retval;

        atomic_set_mask(ZFCP_STATUS_COMMON_OPENING,
                        &erp_action->adapter->status);
        retval = zfcp_erp_adapter_strategy_generic(erp_action, 0);
        atomic_clear_mask(ZFCP_STATUS_COMMON_OPENING,
                          &erp_action->adapter->status);

        return retval;
}

/*
 * function:    zfcp_register_adapter
 *
 * purpose:     allocate the irq associated with this devno and register
 *              the FSF adapter with the SCSI stack
 *
 * returns:
 */
static int
zfcp_erp_adapter_strategy_generic(struct zfcp_erp_action *erp_action, int close)
{
        int retval = ZFCP_ERP_SUCCEEDED;

        if (close)
                goto close_only;

        retval = zfcp_erp_adapter_strategy_open_qdio(erp_action);
        if (retval != ZFCP_ERP_SUCCEEDED)
                goto failed_qdio;

        retval = zfcp_erp_adapter_strategy_open_fsf(erp_action);
        if (retval != ZFCP_ERP_SUCCEEDED)
                goto failed_openfcp;

        atomic_set_mask(ZFCP_STATUS_COMMON_OPEN, &erp_action->adapter->status);
        goto out;

 close_only:
        atomic_clear_mask(ZFCP_STATUS_COMMON_OPEN,
                          &erp_action->adapter->status);

 failed_openfcp:
        zfcp_close_fsf(erp_action->adapter);
 failed_qdio:
        atomic_clear_mask(ZFCP_STATUS_ADAPTER_XCONFIG_OK |
                          ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
                          ZFCP_STATUS_ADAPTER_XPORT_OK,
                          &erp_action->adapter->status);
 out:
        return retval;
}

/*
 * function:    zfcp_qdio_init
 *
 * purpose:     setup QDIO operation for specified adapter
 *
 * returns:     0 - successful setup
 *              !0 - failed setup
 */
static int
zfcp_erp_adapter_strategy_open_qdio(struct zfcp_erp_action *erp_action)
{
        int retval;
        int i;
        volatile struct qdio_buffer_element *sbale;
        struct zfcp_adapter *adapter = erp_action->adapter;

        if (atomic_test_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status)) {
                ZFCP_LOG_NORMAL("bug: second attempt to set up QDIO on "
                                "adapter %s\n",
                                zfcp_get_busid_by_adapter(adapter));
                goto failed_sanity;
        }

        if (qdio_establish(&adapter->qdio_init_data) != 0) {
                ZFCP_LOG_INFO("error: establishment of QDIO queues failed "
                              "on adapter %s\n",
                              zfcp_get_busid_by_adapter(adapter));
                goto failed_qdio_establish;
        }

        if (qdio_activate(adapter->ccw_device, 0) != 0) {
                ZFCP_LOG_INFO("error: activation of QDIO queues failed "
                              "on adapter %s\n",
                              zfcp_get_busid_by_adapter(adapter));
                goto failed_qdio_activate;
        }

        /*
         * put buffers into response queue,
         */
        for (i = 0; i < QDIO_MAX_BUFFERS_PER_Q; i++) {
                sbale = &(adapter->response_queue.buffer[i]->element[0]);
                sbale->length = 0;
                sbale->flags = SBAL_FLAGS_LAST_ENTRY;
                sbale->addr = NULL;
        }

        ZFCP_LOG_TRACE("calling do_QDIO on adapter %s (flags=0x%x, "
                       "queue_no=%i, index_in_queue=%i, count=%i)\n",
                       zfcp_get_busid_by_adapter(adapter),
                       QDIO_FLAG_SYNC_INPUT, 0, 0, QDIO_MAX_BUFFERS_PER_Q);

        retval = do_QDIO(adapter->ccw_device,
                         QDIO_FLAG_SYNC_INPUT,
                         0, 0, QDIO_MAX_BUFFERS_PER_Q, NULL);

        if (retval) {
                ZFCP_LOG_NORMAL("bug: setup of QDIO failed (retval=%d)\n",
                                retval);
                goto failed_do_qdio;
        } else {
                adapter->response_queue.free_index = 0;
                atomic_set(&adapter->response_queue.free_count, 0);
                ZFCP_LOG_DEBUG("%i buffers successfully enqueued to "
                               "response queue\n", QDIO_MAX_BUFFERS_PER_Q);
        }
        /* set index of first avalable SBALS / number of available SBALS */
        adapter->request_queue.free_index = 0;
        atomic_set(&adapter->request_queue.free_count, QDIO_MAX_BUFFERS_PER_Q);
        adapter->request_queue.distance_from_int = 0;

        /* initialize waitqueue used to wait for free SBALs in requests queue */
        init_waitqueue_head(&adapter->request_wq);

        /* ok, we did it - skip all cleanups for different failures */
        atomic_set_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
        retval = ZFCP_ERP_SUCCEEDED;
        goto out;

 failed_do_qdio:
        /* NOP */

 failed_qdio_activate:
        while (qdio_shutdown(adapter->ccw_device,
                             QDIO_FLAG_CLEANUP_USING_CLEAR) == -EINPROGRESS)
                ssleep(1);

 failed_qdio_establish:
 failed_sanity:
        retval = ZFCP_ERP_FAILED;

 out:
        return retval;
}


static int
zfcp_erp_adapter_strategy_open_fsf(struct zfcp_erp_action *erp_action)
{
        int retval;

        retval = zfcp_erp_adapter_strategy_open_fsf_xconfig(erp_action);
        if (retval == ZFCP_ERP_FAILED)
                return ZFCP_ERP_FAILED;

        retval = zfcp_erp_adapter_strategy_open_fsf_xport(erp_action);
        if (retval == ZFCP_ERP_FAILED)
                return ZFCP_ERP_FAILED;

        return zfcp_erp_adapter_strategy_open_fsf_statusread(erp_action);
}

static int
zfcp_erp_adapter_strategy_open_fsf_xconfig(struct zfcp_erp_action *erp_action)
{
        int retval = ZFCP_ERP_SUCCEEDED;
        int retries;
        int sleep = ZFCP_EXCHANGE_CONFIG_DATA_FIRST_SLEEP;
        struct zfcp_adapter *adapter = erp_action->adapter;

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_XCONFIG_OK, &adapter->status);

        for (retries = ZFCP_EXCHANGE_CONFIG_DATA_RETRIES; retries; retries--) {
                atomic_clear_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
                                  &adapter->status);
                ZFCP_LOG_DEBUG("Doing exchange config data\n");
                write_lock_irq(&adapter->erp_lock);
                zfcp_erp_action_to_running(erp_action);
                write_unlock_irq(&adapter->erp_lock);
                if (zfcp_fsf_exchange_config_data(erp_action)) {
                        retval = ZFCP_ERP_FAILED;
                        ZFCP_LOG_INFO("error:  initiation of exchange of "
                                      "configuration data failed for "
                                      "adapter %s\n",
                                      zfcp_get_busid_by_adapter(adapter));
                        break;
                }
                ZFCP_LOG_DEBUG("Xchange underway\n");

                /*
                 * Why this works:
                 * Both the normal completion handler as well as the timeout
                 * handler will do an 'up' when the 'exchange config data'
                 * request completes or times out. Thus, the signal to go on
                 * won't be lost utilizing this semaphore.
                 * Furthermore, this 'adapter_reopen' action is
                 * guaranteed to be the only action being there (highest action
                 * which prevents other actions from being created).
                 * Resulting from that, the wake signal recognized here
                 * _must_ be the one belonging to the 'exchange config
                 * data' request.
                 */
                zfcp_rec_dbf_event_thread(6, adapter, 1);
                down(&adapter->erp_ready_sem);
                zfcp_rec_dbf_event_thread(7, adapter, 1);
                if (erp_action->status & ZFCP_STATUS_ERP_TIMEDOUT) {
                        ZFCP_LOG_INFO("error: exchange of configuration data "
                                      "for adapter %s timed out\n",
                                      zfcp_get_busid_by_adapter(adapter));
                        break;
                }

                if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
                                     &adapter->status))
                        break;

                ZFCP_LOG_DEBUG("host connection still initialising... "
                               "waiting and retrying...\n");
                /* sleep a little bit before retry */
                ssleep(sleep);
                sleep *= 2;
        }

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
                          &adapter->status);

        if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_XCONFIG_OK,
                              &adapter->status)) {
                ZFCP_LOG_INFO("error: exchange of configuration data for "
                              "adapter %s failed\n",
                              zfcp_get_busid_by_adapter(adapter));
                retval = ZFCP_ERP_FAILED;
        }

        return retval;
}

static int
zfcp_erp_adapter_strategy_open_fsf_xport(struct zfcp_erp_action *erp_action)
{
        int ret;
        struct zfcp_adapter *adapter;

        adapter = erp_action->adapter;
        atomic_clear_mask(ZFCP_STATUS_ADAPTER_XPORT_OK, &adapter->status);

        write_lock_irq(&adapter->erp_lock);
        zfcp_erp_action_to_running(erp_action);
        write_unlock_irq(&adapter->erp_lock);

        ret = zfcp_fsf_exchange_port_data(erp_action);
        if (ret == -EOPNOTSUPP) {
                return ZFCP_ERP_SUCCEEDED;
        } else if (ret) {
                return ZFCP_ERP_FAILED;
        }

        ret = ZFCP_ERP_SUCCEEDED;
        zfcp_rec_dbf_event_thread(8, adapter, 1);
        down(&adapter->erp_ready_sem);
        zfcp_rec_dbf_event_thread(9, adapter, 1);
        if (erp_action->status & ZFCP_STATUS_ERP_TIMEDOUT) {
                ZFCP_LOG_INFO("error: exchange port data timed out (adapter "
                              "%s)\n", zfcp_get_busid_by_adapter(adapter));
                ret = ZFCP_ERP_FAILED;
        }

        /* don't treat as error for the sake of compatibility */
        if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_XPORT_OK, &adapter->status))
                ZFCP_LOG_INFO("warning: exchange port data failed (adapter "
                              "%s\n", zfcp_get_busid_by_adapter(adapter));

        return ret;
}

static int
zfcp_erp_adapter_strategy_open_fsf_statusread(struct zfcp_erp_action
                                              *erp_action)
{
        int retval = ZFCP_ERP_SUCCEEDED;
        int temp_ret;
        struct zfcp_adapter *adapter = erp_action->adapter;
        int i;

        adapter->status_read_failed = 0;
        for (i = 0; i < ZFCP_STATUS_READS_RECOM; i++) {
                temp_ret = zfcp_fsf_status_read(adapter, ZFCP_WAIT_FOR_SBAL);
                if (temp_ret < 0) {
                        ZFCP_LOG_INFO("error: set-up of unsolicited status "
                                      "notification failed on adapter %s\n",
                                      zfcp_get_busid_by_adapter(adapter));
                        retval = ZFCP_ERP_FAILED;
                        i--;
                        break;
                }
        }

        return retval;
}

/*
 * function:
 *
 * purpose:     this routine executes the 'Reopen Physical Port' action
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_SUCCEEDED      - action finished successfully
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_port_forced_strategy(struct zfcp_erp_action *erp_action)
{
        int retval = ZFCP_ERP_FAILED;
        struct zfcp_port *port = erp_action->port;

        switch (erp_action->step) {

                /*
                 * FIXME:
                 * the ULP spec. begs for waiting for oustanding commands
                 */
        case ZFCP_ERP_STEP_UNINITIALIZED:
                zfcp_erp_port_strategy_clearstati(port);
                /*
                 * it would be sufficient to test only the normal open flag
                 * since the phys. open flag cannot be set if the normal
                 * open flag is unset - however, this is for readabilty ...
                 */
                if (atomic_test_mask((ZFCP_STATUS_PORT_PHYS_OPEN |
                                      ZFCP_STATUS_COMMON_OPEN),
                                     &port->status)) {
                        ZFCP_LOG_DEBUG("port 0x%016Lx is open -> trying "
                                       "close physical\n", port->wwpn);
                        retval =
                            zfcp_erp_port_forced_strategy_close(erp_action);
                } else
                        retval = ZFCP_ERP_FAILED;
                break;

        case ZFCP_ERP_STEP_PHYS_PORT_CLOSING:
                if (atomic_test_mask(ZFCP_STATUS_PORT_PHYS_OPEN,
                                     &port->status)) {
                        ZFCP_LOG_DEBUG("close physical failed for port "
                                       "0x%016Lx\n", port->wwpn);
                        retval = ZFCP_ERP_FAILED;
                } else
                        retval = ZFCP_ERP_SUCCEEDED;
                break;
        }

        return retval;
}

/*
 * function:
 *
 * purpose:     this routine executes the 'Reopen Port' action
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_SUCCEEDED      - action finished successfully
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_port_strategy(struct zfcp_erp_action *erp_action)
{
        int retval = ZFCP_ERP_FAILED;
        struct zfcp_port *port = erp_action->port;

        switch (erp_action->step) {

                /*
                 * FIXME:
                 * the ULP spec. begs for waiting for oustanding commands
                 */
        case ZFCP_ERP_STEP_UNINITIALIZED:
                zfcp_erp_port_strategy_clearstati(port);
                if (atomic_test_mask(ZFCP_STATUS_COMMON_OPEN, &port->status)) {
                        ZFCP_LOG_DEBUG("port 0x%016Lx is open -> trying "
                                       "close\n", port->wwpn);
                        retval = zfcp_erp_port_strategy_close(erp_action);
                        goto out;
                }               /* else it's already closed, open it */
                break;

        case ZFCP_ERP_STEP_PORT_CLOSING:
                if (atomic_test_mask(ZFCP_STATUS_COMMON_OPEN, &port->status)) {
                        ZFCP_LOG_DEBUG("close failed for port 0x%016Lx\n",
                                       port->wwpn);
                        retval = ZFCP_ERP_FAILED;
                        goto out;
                }               /* else it's closed now, open it */
                break;
        }
        if (erp_action->status & ZFCP_STATUS_ERP_CLOSE_ONLY)
                retval = ZFCP_ERP_EXIT;
        else
                retval = zfcp_erp_port_strategy_open(erp_action);

 out:
        return retval;
}

static int
zfcp_erp_port_strategy_open(struct zfcp_erp_action *erp_action)
{
        int retval;

        if (atomic_test_mask(ZFCP_STATUS_PORT_WKA,
                             &erp_action->port->status))
                retval = zfcp_erp_port_strategy_open_nameserver(erp_action);
        else
                retval = zfcp_erp_port_strategy_open_common(erp_action);

        return retval;
}

static int
zfcp_erp_port_strategy_open_common(struct zfcp_erp_action *erp_action)
{
        int retval = 0;
        struct zfcp_adapter *adapter = erp_action->adapter;
        struct zfcp_port *port = erp_action->port;

        switch (erp_action->step) {

        case ZFCP_ERP_STEP_UNINITIALIZED:
        case ZFCP_ERP_STEP_PHYS_PORT_CLOSING:
        case ZFCP_ERP_STEP_PORT_CLOSING:
                if (fc_host_port_type(adapter->scsi_host) == FC_PORTTYPE_PTP) {
                        if (port->wwpn != adapter->peer_wwpn) {
                                ZFCP_LOG_NORMAL("Failed to open port 0x%016Lx "
                                                "on adapter %s.\nPeer WWPN "
                                                "0x%016Lx does not match\n",
                                                port->wwpn,
                                                zfcp_get_busid_by_adapter(adapter),
                                                adapter->peer_wwpn);
                                zfcp_erp_port_failed(port, 25, NULL);
                                retval = ZFCP_ERP_FAILED;
                                break;
                        }
                        port->d_id = adapter->peer_d_id;
                        atomic_set_mask(ZFCP_STATUS_PORT_DID_DID, &port->status);
                        retval = zfcp_erp_port_strategy_open_port(erp_action);
                        break;
                }
                if (!(adapter->nameserver_port)) {
                        retval = zfcp_nameserver_enqueue(adapter);
                        if (retval != 0) {
                                ZFCP_LOG_NORMAL("error: nameserver port "
                                                "unavailable for adapter %s\n",
                                                zfcp_get_busid_by_adapter(adapter));
                                retval = ZFCP_ERP_FAILED;
                                break;
                        }
                }
                if (!atomic_test_mask(ZFCP_STATUS_COMMON_UNBLOCKED,
                                      &adapter->nameserver_port->status)) {
                        ZFCP_LOG_DEBUG("nameserver port is not open -> open "
                                       "nameserver port\n");
                        /* nameserver port may live again */
                        atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING,
                                        &adapter->nameserver_port->status);
                        if (zfcp_erp_port_reopen(adapter->nameserver_port, 0,
                                                 77, erp_action) >= 0) {
                                erp_action->step =
                                        ZFCP_ERP_STEP_NAMESERVER_OPEN;
                                retval = ZFCP_ERP_CONTINUES;
                        } else
                                retval = ZFCP_ERP_FAILED;
                        break;
                }
                /* else nameserver port is already open, fall through */
        case ZFCP_ERP_STEP_NAMESERVER_OPEN:
                if (!atomic_test_mask(ZFCP_STATUS_COMMON_OPEN,
                                      &adapter->nameserver_port->status)) {
                        ZFCP_LOG_DEBUG("open failed for nameserver port\n");
                        retval = ZFCP_ERP_FAILED;
                } else {
                        ZFCP_LOG_DEBUG("nameserver port is open -> "
                                       "nameserver look-up for port 0x%016Lx\n",
                                       port->wwpn);
                        retval = zfcp_erp_port_strategy_open_common_lookup
                                (erp_action);
                }
                break;

        case ZFCP_ERP_STEP_NAMESERVER_LOOKUP:
                if (!atomic_test_mask(ZFCP_STATUS_PORT_DID_DID, &port->status)) {
                        if (atomic_test_mask
                            (ZFCP_STATUS_PORT_INVALID_WWPN, &port->status)) {
                                ZFCP_LOG_DEBUG("nameserver look-up failed "
                                               "for port 0x%016Lx "
                                               "(misconfigured WWPN?)\n",
                                               port->wwpn);
                                zfcp_erp_port_failed(port, 26, NULL);
                                retval = ZFCP_ERP_EXIT;
                        } else {
                                ZFCP_LOG_DEBUG("nameserver look-up failed for "
                                               "port 0x%016Lx\n", port->wwpn);
                                retval = ZFCP_ERP_FAILED;
                        }
                } else {
                        ZFCP_LOG_DEBUG("port 0x%016Lx has d_id=0x%06x -> "
                                       "trying open\n", port->wwpn, port->d_id);
                        retval = zfcp_erp_port_strategy_open_port(erp_action);
                }
                break;

        case ZFCP_ERP_STEP_PORT_OPENING:
                /* D_ID might have changed during open */
                if (atomic_test_mask((ZFCP_STATUS_COMMON_OPEN |
                                      ZFCP_STATUS_PORT_DID_DID),
                                     &port->status)) {
                        ZFCP_LOG_DEBUG("port 0x%016Lx is open\n", port->wwpn);
                        retval = ZFCP_ERP_SUCCEEDED;
                } else {
                        ZFCP_LOG_DEBUG("open failed for port 0x%016Lx\n",
                                       port->wwpn);
                        retval = ZFCP_ERP_FAILED;
                }
                break;

        default:
                ZFCP_LOG_NORMAL("bug: unknown erp step 0x%08x\n",
                                erp_action->step);
                retval = ZFCP_ERP_FAILED;
        }

        return retval;
}

static int
zfcp_erp_port_strategy_open_nameserver(struct zfcp_erp_action *erp_action)
{
        int retval;
        struct zfcp_port *port = erp_action->port;

        switch (erp_action->step) {

        case ZFCP_ERP_STEP_UNINITIALIZED:
        case ZFCP_ERP_STEP_PHYS_PORT_CLOSING:
        case ZFCP_ERP_STEP_PORT_CLOSING:
                ZFCP_LOG_DEBUG("port 0x%016Lx has d_id=0x%06x -> trying open\n",
                               port->wwpn, port->d_id);
                retval = zfcp_erp_port_strategy_open_port(erp_action);
                break;

        case ZFCP_ERP_STEP_PORT_OPENING:
                if (atomic_test_mask(ZFCP_STATUS_COMMON_OPEN, &port->status)) {
                        ZFCP_LOG_DEBUG("WKA port is open\n");
                        retval = ZFCP_ERP_SUCCEEDED;
                } else {
                        ZFCP_LOG_DEBUG("open failed for WKA port\n");
                        retval = ZFCP_ERP_FAILED;
                }
                /* this is needed anyway (dont care for retval of wakeup) */
                ZFCP_LOG_DEBUG("continue other open port operations\n");
                zfcp_erp_port_strategy_open_nameserver_wakeup(erp_action);
                break;

        default:
                ZFCP_LOG_NORMAL("bug: unknown erp step 0x%08x\n",
                                erp_action->step);
                retval = ZFCP_ERP_FAILED;
        }

        return retval;
}

/*
 * function:
 *
 * purpose:     makes the erp thread continue with reopen (physical) port
 *              actions which have been paused until the name server port
 *              is opened (or failed)
 *
 * returns:     0       (a kind of void retval, its not used)
 */
static int
zfcp_erp_port_strategy_open_nameserver_wakeup(struct zfcp_erp_action
                                              *ns_erp_action)
{
        int retval = 0;
        unsigned long flags;
        struct zfcp_adapter *adapter = ns_erp_action->adapter;
        struct zfcp_erp_action *erp_action, *tmp;

        read_lock_irqsave(&adapter->erp_lock, flags);
        list_for_each_entry_safe(erp_action, tmp, &adapter->erp_running_head,
                                 list) {
                if (erp_action->step == ZFCP_ERP_STEP_NAMESERVER_OPEN) {
                        if (atomic_test_mask(
                                    ZFCP_STATUS_COMMON_ERP_FAILED,
                                    &adapter->nameserver_port->status))
                                zfcp_erp_port_failed(erp_action->port, 27,
                                                     NULL);
                        zfcp_erp_action_ready(erp_action);
                }
        }
        read_unlock_irqrestore(&adapter->erp_lock, flags);

        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_port_forced_strategy_close(struct zfcp_erp_action *erp_action)
{
        int retval;

        retval = zfcp_fsf_close_physical_port(erp_action);
        if (retval == -ENOMEM) {
                retval = ZFCP_ERP_NOMEM;
                goto out;
        }
        erp_action->step = ZFCP_ERP_STEP_PHYS_PORT_CLOSING;
        if (retval != 0) {
                /* could not send 'open', fail */
                retval = ZFCP_ERP_FAILED;
                goto out;
        }
        retval = ZFCP_ERP_CONTINUES;
 out:
        return retval;
}

static int
zfcp_erp_port_strategy_clearstati(struct zfcp_port *port)
{
        int retval = 0;

        atomic_clear_mask(ZFCP_STATUS_COMMON_OPENING |
                          ZFCP_STATUS_COMMON_CLOSING |
                          ZFCP_STATUS_COMMON_ACCESS_DENIED |
                          ZFCP_STATUS_PORT_DID_DID |
                          ZFCP_STATUS_PORT_PHYS_CLOSING |
                          ZFCP_STATUS_PORT_INVALID_WWPN,
                          &port->status);
        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_port_strategy_close(struct zfcp_erp_action *erp_action)
{
        int retval;

        retval = zfcp_fsf_close_port(erp_action);
        if (retval == -ENOMEM) {
                retval = ZFCP_ERP_NOMEM;
                goto out;
        }
        erp_action->step = ZFCP_ERP_STEP_PORT_CLOSING;
        if (retval != 0) {
                /* could not send 'close', fail */
                retval = ZFCP_ERP_FAILED;
                goto out;
        }
        retval = ZFCP_ERP_CONTINUES;
 out:
        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_port_strategy_open_port(struct zfcp_erp_action *erp_action)
{
        int retval;

        retval = zfcp_fsf_open_port(erp_action);
        if (retval == -ENOMEM) {
                retval = ZFCP_ERP_NOMEM;
                goto out;
        }
        erp_action->step = ZFCP_ERP_STEP_PORT_OPENING;
        if (retval != 0) {
                /* could not send 'open', fail */
                retval = ZFCP_ERP_FAILED;
                goto out;
        }
        retval = ZFCP_ERP_CONTINUES;
 out:
        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_port_strategy_open_common_lookup(struct zfcp_erp_action *erp_action)
{
        int retval;

        retval = zfcp_ns_gid_pn_request(erp_action);
        if (retval == -ENOMEM) {
                retval = ZFCP_ERP_NOMEM;
                goto out;
        }
        erp_action->step = ZFCP_ERP_STEP_NAMESERVER_LOOKUP;
        if (retval != 0) {
                /* could not send nameserver request, fail */
                retval = ZFCP_ERP_FAILED;
                goto out;
        }
        retval = ZFCP_ERP_CONTINUES;
 out:
        return retval;
}

/*
 * function:
 *
 * purpose:     this routine executes the 'Reopen Unit' action
 *              currently no retries
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_SUCCEEDED      - action finished successfully
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_unit_strategy(struct zfcp_erp_action *erp_action)
{
        int retval = ZFCP_ERP_FAILED;
        struct zfcp_unit *unit = erp_action->unit;

        switch (erp_action->step) {

                /*
                 * FIXME:
                 * the ULP spec. begs for waiting for oustanding commands
                 */
        case ZFCP_ERP_STEP_UNINITIALIZED:
                zfcp_erp_unit_strategy_clearstati(unit);
                if (atomic_test_mask(ZFCP_STATUS_COMMON_OPEN, &unit->status)) {
                        ZFCP_LOG_DEBUG("unit 0x%016Lx is open -> "
                                       "trying close\n", unit->fcp_lun);
                        retval = zfcp_erp_unit_strategy_close(erp_action);
                        break;
                }
                /* else it's already closed, fall through */
        case ZFCP_ERP_STEP_UNIT_CLOSING:
                if (atomic_test_mask(ZFCP_STATUS_COMMON_OPEN, &unit->status)) {
                        ZFCP_LOG_DEBUG("close failed for unit 0x%016Lx\n",
                                       unit->fcp_lun);
                        retval = ZFCP_ERP_FAILED;
                } else {
                        if (erp_action->status & ZFCP_STATUS_ERP_CLOSE_ONLY)
                                retval = ZFCP_ERP_EXIT;
                        else {
                                ZFCP_LOG_DEBUG("unit 0x%016Lx is not open -> "
                                               "trying open\n", unit->fcp_lun);
                                retval =
                                    zfcp_erp_unit_strategy_open(erp_action);
                        }
                }
                break;

        case ZFCP_ERP_STEP_UNIT_OPENING:
                if (atomic_test_mask(ZFCP_STATUS_COMMON_OPEN, &unit->status)) {
                        ZFCP_LOG_DEBUG("unit 0x%016Lx is open\n",
                                       unit->fcp_lun);
                        retval = ZFCP_ERP_SUCCEEDED;
                } else {
                        ZFCP_LOG_DEBUG("open failed for unit 0x%016Lx\n",
                                       unit->fcp_lun);
                        retval = ZFCP_ERP_FAILED;
                }
                break;
        }

        return retval;
}

static int
zfcp_erp_unit_strategy_clearstati(struct zfcp_unit *unit)
{
        int retval = 0;

        atomic_clear_mask(ZFCP_STATUS_COMMON_OPENING |
                          ZFCP_STATUS_COMMON_CLOSING |
                          ZFCP_STATUS_COMMON_ACCESS_DENIED |
                          ZFCP_STATUS_UNIT_SHARED |
                          ZFCP_STATUS_UNIT_READONLY,
                          &unit->status);

        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_unit_strategy_close(struct zfcp_erp_action *erp_action)
{
        int retval;

        retval = zfcp_fsf_close_unit(erp_action);
        if (retval == -ENOMEM) {
                retval = ZFCP_ERP_NOMEM;
                goto out;
        }
        erp_action->step = ZFCP_ERP_STEP_UNIT_CLOSING;
        if (retval != 0) {
                /* could not send 'close', fail */
                retval = ZFCP_ERP_FAILED;
                goto out;
        }
        retval = ZFCP_ERP_CONTINUES;

 out:
        return retval;
}

/*
 * function:
 *
 * purpose:
 *
 * returns:     ZFCP_ERP_CONTINUES      - action continues (asynchronously)
 *              ZFCP_ERP_FAILED         - action finished unsuccessfully
 */
static int
zfcp_erp_unit_strategy_open(struct zfcp_erp_action *erp_action)
{
        int retval;

        retval = zfcp_fsf_open_unit(erp_action);
        if (retval == -ENOMEM) {
                retval = ZFCP_ERP_NOMEM;
                goto out;
        }
        erp_action->step = ZFCP_ERP_STEP_UNIT_OPENING;
        if (retval != 0) {
                /* could not send 'open', fail */
                retval = ZFCP_ERP_FAILED;
                goto out;
        }
        retval = ZFCP_ERP_CONTINUES;
 out:
        return retval;
}

void zfcp_erp_start_timer(struct zfcp_fsf_req *fsf_req)
{
        BUG_ON(!fsf_req->erp_action);
        fsf_req->timer.function = zfcp_erp_timeout_handler;
        fsf_req->timer.data = (unsigned long) fsf_req->erp_action;
        fsf_req->timer.expires = jiffies + ZFCP_ERP_FSFREQ_TIMEOUT;
        add_timer(&fsf_req->timer);
}

/*
 * function:
 *
 * purpose:     enqueue the specified error recovery action, if needed
 *
 * returns:
 */
static int zfcp_erp_action_enqueue(int want, struct zfcp_adapter *adapter,
                                   struct zfcp_port *port,
                                   struct zfcp_unit *unit, u8 id, void *ref)
{
        int retval = 1, need = want;
        struct zfcp_erp_action *erp_action = NULL;
        u32 status = 0;

        /*
         * We need some rules here which check whether we really need
         * this action or whether we should just drop it.
         * E.g. if there is a unfinished 'Reopen Port' request then we drop a
         * 'Reopen Unit' request for an associated unit since we can't
         * satisfy this request now. A 'Reopen Port' action will trigger
         * 'Reopen Unit' actions when it completes.
         * Thus, there are only actions in the queue which can immediately be
         * executed. This makes the processing of the action queue more
         * efficient.
         */

        if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP,
                              &adapter->status))
                return -EIO;

        /* check whether we really need this */
        switch (want) {
        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                if (atomic_test_mask
                    (ZFCP_STATUS_COMMON_ERP_INUSE, &unit->status)) {
                        goto out;
                }
                if (!atomic_test_mask
                    (ZFCP_STATUS_COMMON_RUNNING, &port->status) ||
                    atomic_test_mask
                    (ZFCP_STATUS_COMMON_ERP_FAILED, &port->status)) {
                        goto out;
                }
                if (!atomic_test_mask
                    (ZFCP_STATUS_COMMON_UNBLOCKED, &port->status))
                        need = ZFCP_ERP_ACTION_REOPEN_PORT;
                /* fall through !!! */

        case ZFCP_ERP_ACTION_REOPEN_PORT:
                if (atomic_test_mask
                    (ZFCP_STATUS_COMMON_ERP_INUSE, &port->status)) {
                        goto out;
                }
                /* fall through !!! */

        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
                if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_INUSE,
                                     &port->status)) {
                        if (port->erp_action.action !=
                            ZFCP_ERP_ACTION_REOPEN_PORT_FORCED) {
                                ZFCP_LOG_INFO("dropped erp action %i (port "
                                              "0x%016Lx, action in use: %i)\n",
                                              want, port->wwpn,
                                              port->erp_action.action);
                        }
                        goto out;
                }
                if (!atomic_test_mask
                    (ZFCP_STATUS_COMMON_RUNNING, &adapter->status) ||
                    atomic_test_mask
                    (ZFCP_STATUS_COMMON_ERP_FAILED, &adapter->status)) {
                        goto out;
                }
                if (!atomic_test_mask
                    (ZFCP_STATUS_COMMON_UNBLOCKED, &adapter->status))
                        need = ZFCP_ERP_ACTION_REOPEN_ADAPTER;
                /* fall through !!! */

        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                if (atomic_test_mask
                    (ZFCP_STATUS_COMMON_ERP_INUSE, &adapter->status)) {
                        goto out;
                }
                break;

        default:
                ZFCP_LOG_NORMAL("bug: unknown erp action requested "
                                "on adapter %s (action=%d)\n",
                                zfcp_get_busid_by_adapter(adapter), want);
                goto out;
        }

        /* check whether we need something stronger first */
        if (need) {
                ZFCP_LOG_DEBUG("stronger erp action %d needed before "
                               "erp action %d on adapter %s\n",
                               need, want, zfcp_get_busid_by_adapter(adapter));
        }

        /* mark adapter to have some error recovery pending */
        atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_PENDING, &adapter->status);

        /* setup error recovery action */
        switch (need) {

        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                zfcp_unit_get(unit);
                atomic_set_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &unit->status);
                erp_action = &unit->erp_action;
                if (!atomic_test_mask
                    (ZFCP_STATUS_COMMON_RUNNING, &unit->status))
                        status = ZFCP_STATUS_ERP_CLOSE_ONLY;
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT:
        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
                zfcp_port_get(port);
                zfcp_erp_action_dismiss_port(port);
                atomic_set_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &port->status);
                erp_action = &port->erp_action;
                if (!atomic_test_mask
                    (ZFCP_STATUS_COMMON_RUNNING, &port->status))
                        status = ZFCP_STATUS_ERP_CLOSE_ONLY;
                break;

        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                zfcp_adapter_get(adapter);
                zfcp_erp_action_dismiss_adapter(adapter);
                atomic_set_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &adapter->status);
                erp_action = &adapter->erp_action;
                if (!atomic_test_mask
                    (ZFCP_STATUS_COMMON_RUNNING, &adapter->status))
                        status = ZFCP_STATUS_ERP_CLOSE_ONLY;
                break;
        }

        memset(erp_action, 0, sizeof (struct zfcp_erp_action));
        erp_action->adapter = adapter;
        erp_action->port = port;
        erp_action->unit = unit;
        erp_action->action = need;
        erp_action->status = status;

        ++adapter->erp_total_count;

        /* finally put it into 'ready' queue and kick erp thread */
        list_add_tail(&erp_action->list, &adapter->erp_ready_head);
        up(&adapter->erp_ready_sem);
        zfcp_rec_dbf_event_thread(1, adapter, 0);
        retval = 0;
 out:
        zfcp_rec_dbf_event_trigger(id, ref, want, need, erp_action,
                                   adapter, port, unit);
        return retval;
}

static int
zfcp_erp_action_dequeue(struct zfcp_erp_action *erp_action)
{
        int retval = 0;
        struct zfcp_adapter *adapter = erp_action->adapter;

        --adapter->erp_total_count;
        if (erp_action->status & ZFCP_STATUS_ERP_LOWMEM) {
                --adapter->erp_low_mem_count;
                erp_action->status &= ~ZFCP_STATUS_ERP_LOWMEM;
        }

        list_del(&erp_action->list);
        zfcp_rec_dbf_event_action(144, erp_action);

        switch (erp_action->action) {
        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                atomic_clear_mask(ZFCP_STATUS_COMMON_ERP_INUSE,
                                  &erp_action->unit->status);
                break;
        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
        case ZFCP_ERP_ACTION_REOPEN_PORT:
                atomic_clear_mask(ZFCP_STATUS_COMMON_ERP_INUSE,
                                  &erp_action->port->status);
                break;
        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                atomic_clear_mask(ZFCP_STATUS_COMMON_ERP_INUSE,
                                  &erp_action->adapter->status);
                break;
        default:
                /* bug */
                break;
        }
        return retval;
}

/**
 * zfcp_erp_action_cleanup
 *
 * Register unit with scsi stack if appropriate and fix reference counts.
 * Note: Temporary units are not registered with scsi stack.
 */
static void
zfcp_erp_action_cleanup(int action, struct zfcp_adapter *adapter,
                        struct zfcp_port *port, struct zfcp_unit *unit,
                        int result)
{
        switch (action) {
        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                if ((result == ZFCP_ERP_SUCCEEDED)
                    && (!atomic_test_mask(ZFCP_STATUS_UNIT_TEMPORARY,
                                          &unit->status))
                    && !unit->device
                    && port->rport) {
                        atomic_set_mask(ZFCP_STATUS_UNIT_REGISTERED,
                                        &unit->status);
                        if (atomic_test_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING,
                                             &unit->status) == 0)
                                zfcp_erp_schedule_work(unit);
                }
                zfcp_unit_put(unit);
                break;
        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
        case ZFCP_ERP_ACTION_REOPEN_PORT:
                if (atomic_test_mask(ZFCP_STATUS_PORT_NO_WWPN,
                                     &port->status)) {
                        zfcp_port_put(port);
                        break;
                }

                if ((result == ZFCP_ERP_SUCCEEDED)
                    && !port->rport) {
                        struct fc_rport_identifiers ids;
                        ids.node_name = port->wwnn;
                        ids.port_name = port->wwpn;
                        ids.port_id = port->d_id;
                        ids.roles = FC_RPORT_ROLE_FCP_TARGET;
                        port->rport =
                                fc_remote_port_add(adapter->scsi_host, 0, &ids);
                        if (!port->rport)
                                ZFCP_LOG_NORMAL("failed registration of rport"
                                                "(adapter %s, wwpn=0x%016Lx)\n",
                                                zfcp_get_busid_by_port(port),
                                                port->wwpn);
                        else {
                                scsi_target_unblock(&port->rport->dev);
                                port->rport->maxframe_size = port->maxframe_size;
                                port->rport->supported_classes =
                                        port->supported_classes;
                        }
                }
                if ((result != ZFCP_ERP_SUCCEEDED) && port->rport) {
                        fc_remote_port_delete(port->rport);
                        port->rport = NULL;
                }
                zfcp_port_put(port);
                break;
        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                if (result != ZFCP_ERP_SUCCEEDED) {
                        list_for_each_entry(port, &adapter->port_list_head, list)
                                if (port->rport &&
                                    !atomic_test_mask(ZFCP_STATUS_PORT_WKA,
                                                      &port->status)) {
                                        fc_remote_port_delete(port->rport);
                                        port->rport = NULL;
                                }
                }
                zfcp_adapter_put(adapter);
                break;
        default:
                break;
        }
}


static void zfcp_erp_action_dismiss_adapter(struct zfcp_adapter *adapter)
{
        struct zfcp_port *port;

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &adapter->status))
                zfcp_erp_action_dismiss(&adapter->erp_action);
        else
                list_for_each_entry(port, &adapter->port_list_head, list)
                    zfcp_erp_action_dismiss_port(port);
}

static void zfcp_erp_action_dismiss_port(struct zfcp_port *port)
{
        struct zfcp_unit *unit;

        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &port->status))
                zfcp_erp_action_dismiss(&port->erp_action);
        else
                list_for_each_entry(unit, &port->unit_list_head, list)
                    zfcp_erp_action_dismiss_unit(unit);
}

static void zfcp_erp_action_dismiss_unit(struct zfcp_unit *unit)
{
        if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &unit->status))
                zfcp_erp_action_dismiss(&unit->erp_action);
}

static void zfcp_erp_action_to_running(struct zfcp_erp_action *erp_action)
{
        list_move(&erp_action->list, &erp_action->adapter->erp_running_head);
        zfcp_rec_dbf_event_action(145, erp_action);
}

static void zfcp_erp_action_to_ready(struct zfcp_erp_action *erp_action)
{
        list_move(&erp_action->list, &erp_action->adapter->erp_ready_head);
        zfcp_rec_dbf_event_action(146, erp_action);
}

void zfcp_erp_port_boxed(struct zfcp_port *port, u8 id, void *ref)
{
        unsigned long flags;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        zfcp_erp_modify_port_status(port, id, ref,
                                    ZFCP_STATUS_COMMON_ACCESS_BOXED, ZFCP_SET);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
        zfcp_erp_port_reopen(port, ZFCP_STATUS_COMMON_ERP_FAILED, id, ref);
}

void zfcp_erp_unit_boxed(struct zfcp_unit *unit, u8 id, void *ref)
{
        zfcp_erp_modify_unit_status(unit, id, ref,
                                    ZFCP_STATUS_COMMON_ACCESS_BOXED, ZFCP_SET);
        zfcp_erp_unit_reopen(unit, ZFCP_STATUS_COMMON_ERP_FAILED, id, ref);
}

void zfcp_erp_port_access_denied(struct zfcp_port *port, u8 id, void *ref)
{
        unsigned long flags;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        zfcp_erp_modify_port_status(port, id, ref,
                                    ZFCP_STATUS_COMMON_ERP_FAILED |
                                    ZFCP_STATUS_COMMON_ACCESS_DENIED, ZFCP_SET);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
}

void zfcp_erp_unit_access_denied(struct zfcp_unit *unit, u8 id, void *ref)
{
        zfcp_erp_modify_unit_status(unit, id, ref,
                                    ZFCP_STATUS_COMMON_ERP_FAILED |
                                    ZFCP_STATUS_COMMON_ACCESS_DENIED, ZFCP_SET);
}

void zfcp_erp_adapter_access_changed(struct zfcp_adapter *adapter, u8 id,
                                     void *ref)
{
        struct zfcp_port *port;
        unsigned long flags;

        if (adapter->connection_features & FSF_FEATURE_NPIV_MODE)
                return;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        if (adapter->nameserver_port)
                zfcp_erp_port_access_changed(adapter->nameserver_port, id, ref);
        list_for_each_entry(port, &adapter->port_list_head, list)
                if (port != adapter->nameserver_port)
                        zfcp_erp_port_access_changed(port, id, ref);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
}

void zfcp_erp_port_access_changed(struct zfcp_port *port, u8 id, void *ref)
{
        struct zfcp_adapter *adapter = port->adapter;
        struct zfcp_unit *unit;

        if (!atomic_test_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED,
                              &port->status) &&
            !atomic_test_mask(ZFCP_STATUS_COMMON_ACCESS_BOXED,
                              &port->status)) {
                if (!atomic_test_mask(ZFCP_STATUS_PORT_WKA, &port->status))
                        list_for_each_entry(unit, &port->unit_list_head, list)
                                zfcp_erp_unit_access_changed(unit, id, ref);
                return;
        }

        ZFCP_LOG_NORMAL("reopen of port 0x%016Lx on adapter %s "
                        "(due to ACT update)\n",
                        port->wwpn, zfcp_get_busid_by_adapter(adapter));
        if (zfcp_erp_port_reopen(port, ZFCP_STATUS_COMMON_ERP_FAILED, id, ref))
                ZFCP_LOG_NORMAL("failed reopen of port"
                                "(adapter %s, wwpn=0x%016Lx)\n",
                                zfcp_get_busid_by_adapter(adapter), port->wwpn);
}

void zfcp_erp_unit_access_changed(struct zfcp_unit *unit, u8 id, void *ref)
{
        struct zfcp_adapter *adapter = unit->port->adapter;

        if (!atomic_test_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED,
                              &unit->status) &&
            !atomic_test_mask(ZFCP_STATUS_COMMON_ACCESS_BOXED,
                              &unit->status))
                return;

        ZFCP_LOG_NORMAL("reopen of unit 0x%016Lx on port 0x%016Lx "
                        " on adapter %s (due to ACT update)\n",
                        unit->fcp_lun, unit->port->wwpn,
                        zfcp_get_busid_by_adapter(adapter));
        if (zfcp_erp_unit_reopen(unit, ZFCP_STATUS_COMMON_ERP_FAILED, id, ref))
                ZFCP_LOG_NORMAL("failed reopen of unit (adapter %s, "
                                "wwpn=0x%016Lx, fcp_lun=0x%016Lx)\n",
                                zfcp_get_busid_by_adapter(adapter),
                                unit->port->wwpn, unit->fcp_lun);
}

#undef ZFCP_LOG_AREA