proc tty: add struct tty_operations::proc_fops

[linux-2.6/mini2440.git] / drivers / s390 / scsi / zfcp_erp.c

/*
 * zfcp device driver
 *
 * Error Recovery Procedures (ERP).
 *
 * Copyright IBM Corporation 2002, 2009
 */

#define KMSG_COMPONENT "zfcp"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include "zfcp_ext.h"

#define ZFCP_MAX_ERPS                   3

enum zfcp_erp_act_flags {
        ZFCP_STATUS_ERP_TIMEDOUT        = 0x10000000,
        ZFCP_STATUS_ERP_CLOSE_ONLY      = 0x01000000,
        ZFCP_STATUS_ERP_DISMISSING      = 0x00100000,
        ZFCP_STATUS_ERP_DISMISSED       = 0x00200000,
        ZFCP_STATUS_ERP_LOWMEM          = 0x00400000,
};

enum zfcp_erp_steps {
        ZFCP_ERP_STEP_UNINITIALIZED     = 0x0000,
        ZFCP_ERP_STEP_FSF_XCONFIG       = 0x0001,
        ZFCP_ERP_STEP_PHYS_PORT_CLOSING = 0x0010,
        ZFCP_ERP_STEP_PORT_CLOSING      = 0x0100,
        ZFCP_ERP_STEP_NAMESERVER_LOOKUP = 0x0400,
        ZFCP_ERP_STEP_PORT_OPENING      = 0x0800,
        ZFCP_ERP_STEP_UNIT_CLOSING      = 0x1000,
        ZFCP_ERP_STEP_UNIT_OPENING      = 0x2000,
};

enum zfcp_erp_act_type {
        ZFCP_ERP_ACTION_REOPEN_UNIT        = 1,
        ZFCP_ERP_ACTION_REOPEN_PORT        = 2,
        ZFCP_ERP_ACTION_REOPEN_PORT_FORCED = 3,
        ZFCP_ERP_ACTION_REOPEN_ADAPTER     = 4,
};

enum zfcp_erp_act_state {
        ZFCP_ERP_ACTION_RUNNING = 1,
        ZFCP_ERP_ACTION_READY   = 2,
};

enum zfcp_erp_act_result {
        ZFCP_ERP_SUCCEEDED = 0,
        ZFCP_ERP_FAILED    = 1,
        ZFCP_ERP_CONTINUES = 2,
        ZFCP_ERP_EXIT      = 3,
        ZFCP_ERP_DISMISSED = 4,
        ZFCP_ERP_NOMEM     = 5,
};

static void zfcp_erp_adapter_block(struct zfcp_adapter *adapter, int mask)
{
        zfcp_erp_modify_adapter_status(adapter, "erablk1", NULL,
                                       ZFCP_STATUS_COMMON_UNBLOCKED | mask,
                                       ZFCP_CLEAR);
}

static int zfcp_erp_action_exists(struct zfcp_erp_action *act)
{
        struct zfcp_erp_action *curr_act;

        list_for_each_entry(curr_act, &act->adapter->erp_running_head, list)
                if (act == curr_act)
                        return ZFCP_ERP_ACTION_RUNNING;
        return 0;
}

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

        list_move(&act->list, &act->adapter->erp_ready_head);
        zfcp_rec_dbf_event_action("erardy1", act);
        up(&adapter->erp_ready_sem);
        zfcp_rec_dbf_event_thread("erardy2", adapter);
}

static void zfcp_erp_action_dismiss(struct zfcp_erp_action *act)
{
        act->status |= ZFCP_STATUS_ERP_DISMISSED;
        if (zfcp_erp_action_exists(act) == ZFCP_ERP_ACTION_RUNNING)
                zfcp_erp_action_ready(act);
}

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

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

        if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_ERP_INUSE)
                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_adapter(struct zfcp_adapter *adapter)
{
        struct zfcp_port *port;

        if (atomic_read(&adapter->status) & ZFCP_STATUS_COMMON_ERP_INUSE)
                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 int zfcp_erp_required_act(int want, struct zfcp_adapter *adapter,
                                 struct zfcp_port *port,
                                 struct zfcp_unit *unit)
{
        int need = want;
        int u_status, p_status, a_status;

        switch (want) {
        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                u_status = atomic_read(&unit->status);
                if (u_status & ZFCP_STATUS_COMMON_ERP_INUSE)
                        return 0;
                p_status = atomic_read(&port->status);
                if (!(p_status & ZFCP_STATUS_COMMON_RUNNING) ||
                      p_status & ZFCP_STATUS_COMMON_ERP_FAILED)
                        return 0;
                if (!(p_status & ZFCP_STATUS_COMMON_UNBLOCKED))
                        need = ZFCP_ERP_ACTION_REOPEN_PORT;
                /* fall through */
        case ZFCP_ERP_ACTION_REOPEN_PORT:
        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
                p_status = atomic_read(&port->status);
                if (p_status & ZFCP_STATUS_COMMON_ERP_INUSE)
                        return 0;
                a_status = atomic_read(&adapter->status);
                if (!(a_status & ZFCP_STATUS_COMMON_RUNNING) ||
                      a_status & ZFCP_STATUS_COMMON_ERP_FAILED)
                        return 0;
                if (!(a_status & ZFCP_STATUS_COMMON_UNBLOCKED))
                        need = ZFCP_ERP_ACTION_REOPEN_ADAPTER;
                /* fall through */
        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                a_status = atomic_read(&adapter->status);
                if (a_status & ZFCP_STATUS_COMMON_ERP_INUSE)
                        return 0;
        }

        return need;
}

static struct zfcp_erp_action *zfcp_erp_setup_act(int need,
                                                  struct zfcp_adapter *adapter,
                                                  struct zfcp_port *port,
                                                  struct zfcp_unit *unit)
{
        struct zfcp_erp_action *erp_action;
        u32 status = 0;

        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_read(&unit->status) & ZFCP_STATUS_COMMON_RUNNING))
                        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_read(&port->status) & ZFCP_STATUS_COMMON_RUNNING))
                        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_read(&adapter->status) &
                      ZFCP_STATUS_COMMON_RUNNING))
                        status = ZFCP_STATUS_ERP_CLOSE_ONLY;
                break;

        default:
                return NULL;
        }

        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;

        return erp_action;
}

static int zfcp_erp_action_enqueue(int want, struct zfcp_adapter *adapter,
                                   struct zfcp_port *port,
                                   struct zfcp_unit *unit, char *id, void *ref)
{
        int retval = 1, need;
        struct zfcp_erp_action *act = NULL;

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

        need = zfcp_erp_required_act(want, adapter, port, unit);
        if (!need)
                goto out;

        atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_PENDING, &adapter->status);
        act = zfcp_erp_setup_act(need, adapter, port, unit);
        if (!act)
                goto out;
        ++adapter->erp_total_count;
        list_add_tail(&act->list, &adapter->erp_ready_head);
        up(&adapter->erp_ready_sem);
        zfcp_rec_dbf_event_thread("eracte1", adapter);
        retval = 0;
 out:
        zfcp_rec_dbf_event_trigger(id, ref, want, need, act,
                                   adapter, port, unit);
        return retval;
}

static int _zfcp_erp_adapter_reopen(struct zfcp_adapter *adapter,
                                    int clear_mask, char *id, void *ref)
{
        zfcp_erp_adapter_block(adapter, clear_mask);
        zfcp_scsi_schedule_rports_block(adapter);

        /* ensure propagation of failed status to new devices */
        if (atomic_read(&adapter->status) & ZFCP_STATUS_COMMON_ERP_FAILED) {
                zfcp_erp_adapter_failed(adapter, "erareo1", NULL);
                return -EIO;
        }
        return zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_ADAPTER,
                                       adapter, NULL, NULL, id, ref);
}

/**
 * zfcp_erp_adapter_reopen - Reopen adapter.
 * @adapter: Adapter to reopen.
 * @clear: Status flags to clear.
 * @id: Id for debug trace event.
 * @ref: Reference for debug trace event.
 */
void zfcp_erp_adapter_reopen(struct zfcp_adapter *adapter, int clear,
                             char *id, void *ref)
{
        unsigned long flags;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);
        _zfcp_erp_adapter_reopen(adapter, clear, id, ref);
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
}

/**
 * zfcp_erp_adapter_shutdown - Shutdown adapter.
 * @adapter: Adapter to shut down.
 * @clear: Status flags to clear.
 * @id: Id for debug trace event.
 * @ref: Reference for debug trace event.
 */
void zfcp_erp_adapter_shutdown(struct zfcp_adapter *adapter, int clear,
                               char *id, void *ref)
{
        int flags = ZFCP_STATUS_COMMON_RUNNING | ZFCP_STATUS_COMMON_ERP_FAILED;
        zfcp_erp_adapter_reopen(adapter, clear | flags, id, ref);
}

/**
 * zfcp_erp_port_shutdown - Shutdown port
 * @port: Port to shut down.
 * @clear: Status flags to clear.
 * @id: Id for debug trace event.
 * @ref: Reference for debug trace event.
 */
void zfcp_erp_port_shutdown(struct zfcp_port *port, int clear, char *id,
                            void *ref)
{
        int flags = ZFCP_STATUS_COMMON_RUNNING | ZFCP_STATUS_COMMON_ERP_FAILED;
        zfcp_erp_port_reopen(port, clear | flags, id, ref);
}

/**
 * zfcp_erp_unit_shutdown - Shutdown unit
 * @unit: Unit to shut down.
 * @clear: Status flags to clear.
 * @id: Id for debug trace event.
 * @ref: Reference for debug trace event.
 */
void zfcp_erp_unit_shutdown(struct zfcp_unit *unit, int clear, char *id,
                            void *ref)
{
        int flags = ZFCP_STATUS_COMMON_RUNNING | ZFCP_STATUS_COMMON_ERP_FAILED;
        zfcp_erp_unit_reopen(unit, clear | flags, id, ref);
}

static void zfcp_erp_port_block(struct zfcp_port *port, int clear)
{
        zfcp_erp_modify_port_status(port, "erpblk1", NULL,
                                    ZFCP_STATUS_COMMON_UNBLOCKED | clear,
                                    ZFCP_CLEAR);
}

static void _zfcp_erp_port_forced_reopen(struct zfcp_port *port,
                                         int clear, char *id, void *ref)
{
        zfcp_erp_port_block(port, clear);
        zfcp_scsi_schedule_rport_block(port);

        if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_ERP_FAILED)
                return;

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

/**
 * zfcp_erp_port_forced_reopen - Forced close of port and open again
 * @port: Port to force close and to reopen.
 * @id: Id for debug trace event.
 * @ref: Reference for debug trace event.
 */
void zfcp_erp_port_forced_reopen(struct zfcp_port *port, int clear, char *id,
                                 void *ref)
{
        unsigned long flags;
        struct zfcp_adapter *adapter = port->adapter;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);
        _zfcp_erp_port_forced_reopen(port, clear, id, ref);
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
}

static int _zfcp_erp_port_reopen(struct zfcp_port *port, int clear, char *id,
                                 void *ref)
{
        zfcp_erp_port_block(port, clear);
        zfcp_scsi_schedule_rport_block(port);

        if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_ERP_FAILED) {
                /* ensure propagation of failed status to new devices */
                zfcp_erp_port_failed(port, "erpreo1", NULL);
                return -EIO;
        }

        return zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_PORT,
                                       port->adapter, port, NULL, id, ref);
}

/**
 * zfcp_erp_port_reopen - trigger remote port recovery
 * @port: port to recover
 * @clear_mask: flags in port status to be cleared
 *
 * Returns 0 if recovery has been triggered, < 0 if not.
 */
int zfcp_erp_port_reopen(struct zfcp_port *port, int clear, char *id, void *ref)
{
        unsigned long flags;
        int retval;
        struct zfcp_adapter *adapter = port->adapter;

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

        return retval;
}

static void zfcp_erp_unit_block(struct zfcp_unit *unit, int clear_mask)
{
        zfcp_erp_modify_unit_status(unit, "erublk1", NULL,
                                    ZFCP_STATUS_COMMON_UNBLOCKED | clear_mask,
                                    ZFCP_CLEAR);
}

static void _zfcp_erp_unit_reopen(struct zfcp_unit *unit, int clear, char *id,
                                  void *ref)
{
        struct zfcp_adapter *adapter = unit->port->adapter;

        zfcp_erp_unit_block(unit, clear);

        if (atomic_read(&unit->status) & ZFCP_STATUS_COMMON_ERP_FAILED)
                return;

        zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_UNIT,
                                adapter, unit->port, unit, id, ref);
}

/**
 * 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
 */
void zfcp_erp_unit_reopen(struct zfcp_unit *unit, int clear, char *id,
                          void *ref)
{
        unsigned long flags;
        struct zfcp_port *port = unit->port;
        struct zfcp_adapter *adapter = port->adapter;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);
        _zfcp_erp_unit_reopen(unit, clear, id, ref);
        write_unlock(&adapter->erp_lock);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
}

static int status_change_set(unsigned long mask, atomic_t *status)
{
        return (atomic_read(status) ^ mask) & mask;
}

static int status_change_clear(unsigned long mask, atomic_t *status)
{
        return atomic_read(status) & mask;
}

static void zfcp_erp_adapter_unblock(struct zfcp_adapter *adapter)
{
        if (status_change_set(ZFCP_STATUS_COMMON_UNBLOCKED, &adapter->status))
                zfcp_rec_dbf_event_adapter("eraubl1", NULL, adapter);
        atomic_set_mask(ZFCP_STATUS_COMMON_UNBLOCKED, &adapter->status);
}

static void zfcp_erp_port_unblock(struct zfcp_port *port)
{
        if (status_change_set(ZFCP_STATUS_COMMON_UNBLOCKED, &port->status))
                zfcp_rec_dbf_event_port("erpubl1", NULL, port);
        atomic_set_mask(ZFCP_STATUS_COMMON_UNBLOCKED, &port->status);
}

static void zfcp_erp_unit_unblock(struct zfcp_unit *unit)
{
        if (status_change_set(ZFCP_STATUS_COMMON_UNBLOCKED, &unit->status))
                zfcp_rec_dbf_event_unit("eruubl1", NULL, unit);
        atomic_set_mask(ZFCP_STATUS_COMMON_UNBLOCKED, &unit->status);
}

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("erator1", erp_action);
}

static void zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *act)
{
        struct zfcp_adapter *adapter = act->adapter;

        if (!act->fsf_req)
                return;

        spin_lock(&adapter->req_list_lock);
        if (zfcp_reqlist_find_safe(adapter, act->fsf_req) &&
            act->fsf_req->erp_action == act) {
                if (act->status & (ZFCP_STATUS_ERP_DISMISSED |
                                   ZFCP_STATUS_ERP_TIMEDOUT)) {
                        act->fsf_req->status |= ZFCP_STATUS_FSFREQ_DISMISSED;
                        zfcp_rec_dbf_event_action("erscf_1", act);
                        act->fsf_req->erp_action = NULL;
                }
                if (act->status & ZFCP_STATUS_ERP_TIMEDOUT)
                        zfcp_rec_dbf_event_action("erscf_2", act);
                if (act->fsf_req->status & (ZFCP_STATUS_FSFREQ_COMPLETED |
                                            ZFCP_STATUS_FSFREQ_DISMISSED))
                        act->fsf_req = NULL;
        } else
                act->fsf_req = NULL;
        spin_unlock(&adapter->req_list_lock);
}

/**
 * zfcp_erp_notify - Trigger ERP action.
 * @erp_action: ERP action to continue.
 * @set_mask: ERP action status flags to set.
 */
void zfcp_erp_notify(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);
        if (zfcp_erp_action_exists(erp_action) == ZFCP_ERP_ACTION_RUNNING) {
                erp_action->status |= set_mask;
                zfcp_erp_action_ready(erp_action);
        }
        write_unlock_irqrestore(&adapter->erp_lock, flags);
}

/**
 * zfcp_erp_timeout_handler - Trigger ERP action from timed out ERP request
 * @data: ERP action (from timer data)
 */
void zfcp_erp_timeout_handler(unsigned long data)
{
        struct zfcp_erp_action *act = (struct zfcp_erp_action *) data;
        zfcp_erp_notify(act, ZFCP_STATUS_ERP_TIMEDOUT);
}

static void zfcp_erp_memwait_handler(unsigned long data)
{
        zfcp_erp_notify((struct zfcp_erp_action *)data, 0);
}

static void zfcp_erp_strategy_memwait(struct zfcp_erp_action *erp_action)
{
        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 + HZ;
        add_timer(&erp_action->timer);
}

static void _zfcp_erp_port_reopen_all(struct zfcp_adapter *adapter,
                                      int clear, char *id, void *ref)
{
        struct zfcp_port *port;

        list_for_each_entry(port, &adapter->port_list_head, list)
                _zfcp_erp_port_reopen(port, clear, id, ref);
}

static void _zfcp_erp_unit_reopen_all(struct zfcp_port *port, int clear,
                                      char *id, void *ref)
{
        struct zfcp_unit *unit;

        list_for_each_entry(unit, &port->unit_list_head, list)
                _zfcp_erp_unit_reopen(unit, clear, id, ref);
}

static void zfcp_erp_strategy_followup_actions(struct zfcp_erp_action *act)
{
        struct zfcp_adapter *adapter = act->adapter;
        struct zfcp_port *port = act->port;
        struct zfcp_unit *unit = act->unit;
        u32 status = act->status;

        /* initiate follow-up actions depending on success of finished action */
        switch (act->action) {

        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                if (status == ZFCP_ERP_SUCCEEDED)
                        _zfcp_erp_port_reopen_all(adapter, 0, "ersfa_1", NULL);
                else
                        _zfcp_erp_adapter_reopen(adapter, 0, "ersfa_2", NULL);
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
                if (status == ZFCP_ERP_SUCCEEDED)
                        _zfcp_erp_port_reopen(port, 0, "ersfa_3", NULL);
                else
                        _zfcp_erp_adapter_reopen(adapter, 0, "ersfa_4", NULL);
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT:
                if (status == ZFCP_ERP_SUCCEEDED)
                        _zfcp_erp_unit_reopen_all(port, 0, "ersfa_5", NULL);
                else
                        _zfcp_erp_port_forced_reopen(port, 0, "ersfa_6", NULL);
                break;

        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                if (status != ZFCP_ERP_SUCCEEDED)
                        _zfcp_erp_port_reopen(unit->port, 0, "ersfa_7", NULL);
                break;
        }
}

static void zfcp_erp_wakeup(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);
}

static int zfcp_erp_adapter_strategy_open_qdio(struct zfcp_erp_action *act)
{
        if (zfcp_qdio_open(act->adapter))
                return ZFCP_ERP_FAILED;
        init_waitqueue_head(&act->adapter->request_wq);
        atomic_set_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &act->adapter->status);
        return ZFCP_ERP_SUCCEEDED;
}

static void zfcp_erp_enqueue_ptp_port(struct zfcp_adapter *adapter)
{
        struct zfcp_port *port;
        port = zfcp_port_enqueue(adapter, adapter->peer_wwpn, 0,
                                 adapter->peer_d_id);
        if (IS_ERR(port)) /* error or port already attached */
                return;
        _zfcp_erp_port_reopen(port, 0, "ereptp1", NULL);
}

static int zfcp_erp_adapter_strat_fsf_xconf(struct zfcp_erp_action *erp_action)
{
        int retries;
        int sleep = 1;
        struct zfcp_adapter *adapter = erp_action->adapter;

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_XCONFIG_OK, &adapter->status);

        for (retries = 7; retries; retries--) {
                atomic_clear_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
                                  &adapter->status);
                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)) {
                        atomic_clear_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
                                          &adapter->status);
                        return ZFCP_ERP_FAILED;
                }

                zfcp_rec_dbf_event_thread_lock("erasfx1", adapter);
                down(&adapter->erp_ready_sem);
                zfcp_rec_dbf_event_thread_lock("erasfx2", adapter);
                if (erp_action->status & ZFCP_STATUS_ERP_TIMEDOUT)
                        break;

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

                ssleep(sleep);
                sleep *= 2;
        }

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
                          &adapter->status);

        if (!(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_XCONFIG_OK))
                return ZFCP_ERP_FAILED;

        if (fc_host_port_type(adapter->scsi_host) == FC_PORTTYPE_PTP)
                zfcp_erp_enqueue_ptp_port(adapter);

        return ZFCP_ERP_SUCCEEDED;
}

static int zfcp_erp_adapter_strategy_open_fsf_xport(struct zfcp_erp_action *act)
{
        int ret;
        struct zfcp_adapter *adapter = act->adapter;

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

        ret = zfcp_fsf_exchange_port_data(act);
        if (ret == -EOPNOTSUPP)
                return ZFCP_ERP_SUCCEEDED;
        if (ret)
                return ZFCP_ERP_FAILED;

        zfcp_rec_dbf_event_thread_lock("erasox1", adapter);
        down(&adapter->erp_ready_sem);
        zfcp_rec_dbf_event_thread_lock("erasox2", adapter);
        if (act->status & ZFCP_STATUS_ERP_TIMEDOUT)
                return ZFCP_ERP_FAILED;

        return ZFCP_ERP_SUCCEEDED;
}

static int zfcp_erp_adapter_strategy_open_fsf(struct zfcp_erp_action *act)
{
        if (zfcp_erp_adapter_strat_fsf_xconf(act) == ZFCP_ERP_FAILED)
                return ZFCP_ERP_FAILED;

        if (zfcp_erp_adapter_strategy_open_fsf_xport(act) == ZFCP_ERP_FAILED)
                return ZFCP_ERP_FAILED;

        atomic_set(&act->adapter->stat_miss, 16);
        if (zfcp_status_read_refill(act->adapter))
                return ZFCP_ERP_FAILED;

        return ZFCP_ERP_SUCCEEDED;
}

static void zfcp_erp_adapter_strategy_close(struct zfcp_erp_action *act)
{
        struct zfcp_adapter *adapter = act->adapter;

        /* close queues to ensure that buffers are not accessed by adapter */
        zfcp_qdio_close(adapter);
        zfcp_fsf_req_dismiss_all(adapter);
        adapter->fsf_req_seq_no = 0;
        /* all ports and units are closed */
        zfcp_erp_modify_adapter_status(adapter, "erascl1", NULL,
                                       ZFCP_STATUS_COMMON_OPEN, ZFCP_CLEAR);

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_XCONFIG_OK |
                          ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED, &adapter->status);
}

static int zfcp_erp_adapter_strategy_open(struct zfcp_erp_action *act)
{
        struct zfcp_adapter *adapter = act->adapter;

        if (zfcp_erp_adapter_strategy_open_qdio(act)) {
                atomic_clear_mask(ZFCP_STATUS_ADAPTER_XCONFIG_OK |
                                  ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED,
                                  &adapter->status);
                return ZFCP_ERP_FAILED;
        }

        if (zfcp_erp_adapter_strategy_open_fsf(act)) {
                zfcp_erp_adapter_strategy_close(act);
                return ZFCP_ERP_FAILED;
        }

        atomic_set_mask(ZFCP_STATUS_COMMON_OPEN, &adapter->status);

        return ZFCP_ERP_SUCCEEDED;
}

static int zfcp_erp_adapter_strategy(struct zfcp_erp_action *act)
{
        struct zfcp_adapter *adapter = act->adapter;

        if (atomic_read(&adapter->status) & ZFCP_STATUS_COMMON_OPEN) {
                zfcp_erp_adapter_strategy_close(act);
                if (act->status & ZFCP_STATUS_ERP_CLOSE_ONLY)
                        return ZFCP_ERP_EXIT;
        }

        if (zfcp_erp_adapter_strategy_open(act)) {
                ssleep(8);
                return ZFCP_ERP_FAILED;
        }

        return ZFCP_ERP_SUCCEEDED;
}

static int zfcp_erp_port_forced_strategy_close(struct zfcp_erp_action *act)
{
        int retval;

        retval = zfcp_fsf_close_physical_port(act);
        if (retval == -ENOMEM)
                return ZFCP_ERP_NOMEM;
        act->step = ZFCP_ERP_STEP_PHYS_PORT_CLOSING;
        if (retval)
                return ZFCP_ERP_FAILED;

        return ZFCP_ERP_CONTINUES;
}

static void zfcp_erp_port_strategy_clearstati(struct zfcp_port *port)
{
        atomic_clear_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED, &port->status);
}

static int zfcp_erp_port_forced_strategy(struct zfcp_erp_action *erp_action)
{
        struct zfcp_port *port = erp_action->port;
        int status = atomic_read(&port->status);

        switch (erp_action->step) {
        case ZFCP_ERP_STEP_UNINITIALIZED:
                zfcp_erp_port_strategy_clearstati(port);
                if ((status & ZFCP_STATUS_PORT_PHYS_OPEN) &&
                    (status & ZFCP_STATUS_COMMON_OPEN))
                        return zfcp_erp_port_forced_strategy_close(erp_action);
                else
                        return ZFCP_ERP_FAILED;

        case ZFCP_ERP_STEP_PHYS_PORT_CLOSING:
                if (status & ZFCP_STATUS_PORT_PHYS_OPEN)
                        return ZFCP_ERP_SUCCEEDED;
        }
        return ZFCP_ERP_FAILED;
}

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)
                return ZFCP_ERP_NOMEM;
        erp_action->step = ZFCP_ERP_STEP_PORT_CLOSING;
        if (retval)
                return ZFCP_ERP_FAILED;
        return ZFCP_ERP_CONTINUES;
}

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)
                return ZFCP_ERP_NOMEM;
        erp_action->step = ZFCP_ERP_STEP_PORT_OPENING;
        if (retval)
                return ZFCP_ERP_FAILED;
        return ZFCP_ERP_CONTINUES;
}

static int zfcp_erp_open_ptp_port(struct zfcp_erp_action *act)
{
        struct zfcp_adapter *adapter = act->adapter;
        struct zfcp_port *port = act->port;

        if (port->wwpn != adapter->peer_wwpn) {
                zfcp_erp_port_failed(port, "eroptp1", NULL);
                return ZFCP_ERP_FAILED;
        }
        port->d_id = adapter->peer_d_id;
        return zfcp_erp_port_strategy_open_port(act);
}

void zfcp_erp_port_strategy_open_lookup(struct work_struct *work)
{
        int retval;
        struct zfcp_port *port = container_of(work, struct zfcp_port,
                                              gid_pn_work);

        retval = zfcp_fc_ns_gid_pn(&port->erp_action);
        if (retval == -ENOMEM)
                zfcp_erp_notify(&port->erp_action, ZFCP_ERP_NOMEM);
        port->erp_action.step = ZFCP_ERP_STEP_NAMESERVER_LOOKUP;
        if (retval)
                zfcp_erp_notify(&port->erp_action, ZFCP_ERP_FAILED);
        zfcp_port_put(port);
}

static int zfcp_erp_port_strategy_open_common(struct zfcp_erp_action *act)
{
        struct zfcp_adapter *adapter = act->adapter;
        struct zfcp_port *port = act->port;
        int p_status = atomic_read(&port->status);

        switch (act->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)
                        return zfcp_erp_open_ptp_port(act);
                if (!port->d_id) {
                        zfcp_port_get(port);
                        if (!queue_work(zfcp_data.work_queue,
                                        &port->gid_pn_work))
                                zfcp_port_put(port);
                        return ZFCP_ERP_CONTINUES;
                }
        case ZFCP_ERP_STEP_NAMESERVER_LOOKUP:
                if (!port->d_id)
                        return ZFCP_ERP_FAILED;
                return zfcp_erp_port_strategy_open_port(act);

        case ZFCP_ERP_STEP_PORT_OPENING:
                /* D_ID might have changed during open */
                if (p_status & ZFCP_STATUS_COMMON_OPEN) {
                        if (port->d_id)
                                return ZFCP_ERP_SUCCEEDED;
                        else {
                                act->step = ZFCP_ERP_STEP_PORT_CLOSING;
                                return ZFCP_ERP_CONTINUES;
                        }
                /* fall through otherwise */
                }
        }
        return ZFCP_ERP_FAILED;
}

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

        if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_NOESC)
                goto close_init_done;

        switch (erp_action->step) {
        case ZFCP_ERP_STEP_UNINITIALIZED:
                zfcp_erp_port_strategy_clearstati(port);
                if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_OPEN)
                        return zfcp_erp_port_strategy_close(erp_action);
                break;

        case ZFCP_ERP_STEP_PORT_CLOSING:
                if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_OPEN)
                        return ZFCP_ERP_FAILED;
                break;
        }

close_init_done:
        if (erp_action->status & ZFCP_STATUS_ERP_CLOSE_ONLY)
                return ZFCP_ERP_EXIT;

        return zfcp_erp_port_strategy_open_common(erp_action);
}

static void zfcp_erp_unit_strategy_clearstati(struct zfcp_unit *unit)
{
        atomic_clear_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED |
                          ZFCP_STATUS_UNIT_SHARED |
                          ZFCP_STATUS_UNIT_READONLY,
                          &unit->status);
}

static int zfcp_erp_unit_strategy_close(struct zfcp_erp_action *erp_action)
{
        int retval = zfcp_fsf_close_unit(erp_action);
        if (retval == -ENOMEM)
                return ZFCP_ERP_NOMEM;
        erp_action->step = ZFCP_ERP_STEP_UNIT_CLOSING;
        if (retval)
                return ZFCP_ERP_FAILED;
        return ZFCP_ERP_CONTINUES;
}

static int zfcp_erp_unit_strategy_open(struct zfcp_erp_action *erp_action)
{
        int retval = zfcp_fsf_open_unit(erp_action);
        if (retval == -ENOMEM)
                return ZFCP_ERP_NOMEM;
        erp_action->step = ZFCP_ERP_STEP_UNIT_OPENING;
        if (retval)
                return  ZFCP_ERP_FAILED;
        return ZFCP_ERP_CONTINUES;
}

static int zfcp_erp_unit_strategy(struct zfcp_erp_action *erp_action)
{
        struct zfcp_unit *unit = erp_action->unit;

        switch (erp_action->step) {
        case ZFCP_ERP_STEP_UNINITIALIZED:
                zfcp_erp_unit_strategy_clearstati(unit);
                if (atomic_read(&unit->status) & ZFCP_STATUS_COMMON_OPEN)
                        return zfcp_erp_unit_strategy_close(erp_action);
                /* already closed, fall through */
        case ZFCP_ERP_STEP_UNIT_CLOSING:
                if (atomic_read(&unit->status) & ZFCP_STATUS_COMMON_OPEN)
                        return ZFCP_ERP_FAILED;
                if (erp_action->status & ZFCP_STATUS_ERP_CLOSE_ONLY)
                        return ZFCP_ERP_EXIT;
                return zfcp_erp_unit_strategy_open(erp_action);

        case ZFCP_ERP_STEP_UNIT_OPENING:
                if (atomic_read(&unit->status) & ZFCP_STATUS_COMMON_OPEN)
                        return ZFCP_ERP_SUCCEEDED;
        }
        return ZFCP_ERP_FAILED;
}

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) {
                        dev_err(&unit->port->adapter->ccw_device->dev,
                                "ERP failed for unit 0x%016Lx on "
                                "port 0x%016Lx\n",
                                (unsigned long long)unit->fcp_lun,
                                (unsigned long long)unit->port->wwpn);
                        zfcp_erp_unit_failed(unit, "erusck1", NULL);
                }
                break;
        }

        if (atomic_read(&unit->status) & ZFCP_STATUS_COMMON_ERP_FAILED) {
                zfcp_erp_unit_block(unit, 0);
                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 :
                if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_NOESC) {
                        zfcp_erp_port_block(port, 0);
                        result = ZFCP_ERP_EXIT;
                }
                atomic_inc(&port->erp_counter);
                if (atomic_read(&port->erp_counter) > ZFCP_MAX_ERPS) {
                        dev_err(&port->adapter->ccw_device->dev,
                                "ERP failed for remote port 0x%016Lx\n",
                                (unsigned long long)port->wwpn);
                        zfcp_erp_port_failed(port, "erpsck1", NULL);
                }
                break;
        }

        if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_ERP_FAILED) {
                zfcp_erp_port_block(port, 0);
                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) {
                        dev_err(&adapter->ccw_device->dev,
                                "ERP cannot recover an error "
                                "on the FCP device\n");
                        zfcp_erp_adapter_failed(adapter, "erasck1", NULL);
                }
                break;
        }

        if (atomic_read(&adapter->status) & ZFCP_STATUS_COMMON_ERP_FAILED) {
                zfcp_erp_adapter_block(adapter, 0);
                result = ZFCP_ERP_EXIT;
        }
        return result;
}

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_strat_change_det(atomic_t *target_status, u32 erp_status)
{
        int status = atomic_read(target_status);

        if ((status & ZFCP_STATUS_COMMON_RUNNING) &&
            (erp_status & ZFCP_STATUS_ERP_CLOSE_ONLY))
                return 1; /* take it online */

        if (!(status & ZFCP_STATUS_COMMON_RUNNING) &&
            !(erp_status & ZFCP_STATUS_ERP_CLOSE_ONLY))
                return 1; /* take it offline */

        return 0;
}

static int zfcp_erp_strategy_statechange(struct zfcp_erp_action *act, int ret)
{
        int action = act->action;
        struct zfcp_adapter *adapter = act->adapter;
        struct zfcp_port *port = act->port;
        struct zfcp_unit *unit = act->unit;
        u32 erp_status = act->status;

        switch (action) {
        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                if (zfcp_erp_strat_change_det(&adapter->status, erp_status)) {
                        _zfcp_erp_adapter_reopen(adapter,
                                                 ZFCP_STATUS_COMMON_ERP_FAILED,
                                                 "ersscg1", NULL);
                        return ZFCP_ERP_EXIT;
                }
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
        case ZFCP_ERP_ACTION_REOPEN_PORT:
                if (zfcp_erp_strat_change_det(&port->status, erp_status)) {
                        _zfcp_erp_port_reopen(port,
                                              ZFCP_STATUS_COMMON_ERP_FAILED,
                                              "ersscg2", NULL);
                        return ZFCP_ERP_EXIT;
                }
                break;

        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                if (zfcp_erp_strat_change_det(&unit->status, erp_status)) {
                        _zfcp_erp_unit_reopen(unit,
                                              ZFCP_STATUS_COMMON_ERP_FAILED,
                                              "ersscg3", NULL);
                        return ZFCP_ERP_EXIT;
                }
                break;
        }
        return ret;
}

static void zfcp_erp_action_dequeue(struct zfcp_erp_action *erp_action)
{
        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("eractd1", 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;
        }
}

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

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;

        if (rport && rport->port_state == FC_PORTSTATE_ONLINE)
                scsi_scan_target(&rport->dev, 0, rport->scsi_target_id,
                         scsilun_to_int((struct scsi_lun *)&unit->fcp_lun), 0);
        atomic_clear_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING, &unit->status);
        zfcp_unit_put(unit);
        wake_up(&unit->port->adapter->erp_done_wqh);
        kfree(p);
}

static void zfcp_erp_schedule_work(struct zfcp_unit *unit)
{
        struct zfcp_erp_add_work *p;

        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (!p) {
                dev_err(&unit->port->adapter->ccw_device->dev,
                        "Registering unit 0x%016Lx on port 0x%016Lx failed\n",
                        (unsigned long long)unit->fcp_lun,
                        (unsigned long long)unit->port->wwpn);
                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;
        if (!queue_work(zfcp_data.work_queue, &p->work))
                zfcp_unit_put(unit);
}

static void zfcp_erp_action_cleanup(struct zfcp_erp_action *act, int result)
{
        struct zfcp_adapter *adapter = act->adapter;
        struct zfcp_port *port = act->port;
        struct zfcp_unit *unit = act->unit;

        switch (act->action) {
        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                flush_work(&port->rport_work);
                if ((result == ZFCP_ERP_SUCCEEDED) && !unit->device) {
                        if (!(atomic_read(&unit->status) &
                              ZFCP_STATUS_UNIT_SCSI_WORK_PENDING))
                                zfcp_erp_schedule_work(unit);
                }
                zfcp_unit_put(unit);
                break;

        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
        case ZFCP_ERP_ACTION_REOPEN_PORT:
                if (result == ZFCP_ERP_SUCCEEDED)
                        zfcp_scsi_schedule_rport_register(port);
                zfcp_port_put(port);
                break;

        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                if (result == ZFCP_ERP_SUCCEEDED) {
                        register_service_level(&adapter->service_level);
                        schedule_work(&adapter->scan_work);
                } else
                        unregister_service_level(&adapter->service_level);
                zfcp_adapter_put(adapter);
                break;
        }
}

static int zfcp_erp_strategy_do_action(struct zfcp_erp_action *erp_action)
{
        switch (erp_action->action) {
        case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
                return zfcp_erp_adapter_strategy(erp_action);
        case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
                return zfcp_erp_port_forced_strategy(erp_action);
        case ZFCP_ERP_ACTION_REOPEN_PORT:
                return zfcp_erp_port_strategy(erp_action);
        case ZFCP_ERP_ACTION_REOPEN_UNIT:
                return zfcp_erp_unit_strategy(erp_action);
        }
        return ZFCP_ERP_FAILED;
}

static int zfcp_erp_strategy(struct zfcp_erp_action *erp_action)
{
        int retval;
        struct zfcp_adapter *adapter = erp_action->adapter;
        unsigned long flags;

        read_lock_irqsave(&zfcp_data.config_lock, flags);
        write_lock(&adapter->erp_lock);

        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;
                goto unlock;
        }

        zfcp_erp_action_to_running(erp_action);

        /* no lock to allow for blocking operations */
        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);

        if (erp_action->status & ZFCP_STATUS_ERP_DISMISSED)
                retval = ZFCP_ERP_CONTINUES;

        switch (retval) {
        case ZFCP_ERP_NOMEM:
                if (!(erp_action->status & ZFCP_STATUS_ERP_LOWMEM)) {
                        ++adapter->erp_low_mem_count;
                        erp_action->status |= ZFCP_STATUS_ERP_LOWMEM;
                }
                if (adapter->erp_total_count == adapter->erp_low_mem_count)
                        _zfcp_erp_adapter_reopen(adapter, 0, "erstgy1", NULL);
                else {
                        zfcp_erp_strategy_memwait(erp_action);
                        retval = ZFCP_ERP_CONTINUES;
                }
                goto unlock;

        case ZFCP_ERP_CONTINUES:
                if (erp_action->status & ZFCP_STATUS_ERP_LOWMEM) {
                        --adapter->erp_low_mem_count;
                        erp_action->status &= ~ZFCP_STATUS_ERP_LOWMEM;
                }
                goto unlock;
        }

        retval = zfcp_erp_strategy_check_target(erp_action, retval);
        zfcp_erp_action_dequeue(erp_action);
        retval = zfcp_erp_strategy_statechange(erp_action, retval);
        if (retval == ZFCP_ERP_EXIT)
                goto unlock;
        zfcp_erp_strategy_followup_actions(erp_action);

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

        if (retval != ZFCP_ERP_CONTINUES)
                zfcp_erp_action_cleanup(erp_action, retval);

        return retval;
}

static int zfcp_erp_thread(void *data)
{
        struct zfcp_adapter *adapter = (struct zfcp_adapter *) data;
        struct list_head *next;
        struct zfcp_erp_action *act;
        unsigned long flags;
        int ignore;

        daemonize("zfcperp%s", dev_name(&adapter->ccw_device->dev));
        /* 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_read(&adapter->status) &
                 ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL)) {
                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) {
                        act = list_entry(next, struct zfcp_erp_action, list);

                        /* there is more to come after dismission, no notify */
                        if (zfcp_erp_strategy(act) != ZFCP_ERP_DISMISSED)
                                zfcp_erp_wakeup(adapter);
                }

                zfcp_rec_dbf_event_thread_lock("erthrd1", adapter);
                ignore = down_interruptible(&adapter->erp_ready_sem);
                zfcp_rec_dbf_event_thread_lock("erthrd2", adapter);
        }

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

        return 0;
}

/**
 * zfcp_erp_thread_setup - Start ERP thread for adapter
 * @adapter: Adapter to start the ERP thread for
 *
 * Returns 0 on success or error code from kernel_thread()
 */
int zfcp_erp_thread_setup(struct zfcp_adapter *adapter)
{
        int retval;

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP, &adapter->status);
        retval = kernel_thread(zfcp_erp_thread, adapter, SIGCHLD);
        if (retval < 0) {
                dev_err(&adapter->ccw_device->dev,
                        "Creating an ERP thread for the FCP device failed.\n");
                return retval;
        }
        wait_event(adapter->erp_thread_wqh,
                   atomic_read(&adapter->status) &
                        ZFCP_STATUS_ADAPTER_ERP_THREAD_UP);
        return 0;
}

/**
 * zfcp_erp_thread_kill - Stop ERP thread.
 * @adapter: Adapter where the ERP thread should be stopped.
 *
 * 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.
 */
void zfcp_erp_thread_kill(struct zfcp_adapter *adapter)
{
        atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL, &adapter->status);
        up(&adapter->erp_ready_sem);
        zfcp_rec_dbf_event_thread_lock("erthrk1", adapter);

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

        atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL,
                          &adapter->status);
}

/**
 * zfcp_erp_adapter_failed - Set adapter status to failed.
 * @adapter: Failed adapter.
 * @id: Event id for debug trace.
 * @ref: Reference for debug trace.
 */
void zfcp_erp_adapter_failed(struct zfcp_adapter *adapter, char *id, void *ref)
{
        zfcp_erp_modify_adapter_status(adapter, id, ref,
                                       ZFCP_STATUS_COMMON_ERP_FAILED, ZFCP_SET);
}

/**
 * zfcp_erp_port_failed - Set port status to failed.
 * @port: Failed port.
 * @id: Event id for debug trace.
 * @ref: Reference for debug trace.
 */
void zfcp_erp_port_failed(struct zfcp_port *port, char *id, void *ref)
{
        zfcp_erp_modify_port_status(port, id, ref,
                                    ZFCP_STATUS_COMMON_ERP_FAILED, ZFCP_SET);
}

/**
 * zfcp_erp_unit_failed - Set unit status to failed.
 * @unit: Failed unit.
 * @id: Event id for debug trace.
 * @ref: Reference for debug trace.
 */
void zfcp_erp_unit_failed(struct zfcp_unit *unit, char *id, void *ref)
{
        zfcp_erp_modify_unit_status(unit, id, ref,
                                    ZFCP_STATUS_COMMON_ERP_FAILED, ZFCP_SET);
}

/**
 * zfcp_erp_wait - wait for completion of error recovery on an adapter
 * @adapter: adapter for which to wait for completion of its error recovery
 */
void zfcp_erp_wait(struct zfcp_adapter *adapter)
{
        wait_event(adapter->erp_done_wqh,
                   !(atomic_read(&adapter->status) &
                        ZFCP_STATUS_ADAPTER_ERP_PENDING));
}

/**
 * zfcp_erp_modify_adapter_status - change adapter status bits
 * @adapter: adapter to change the status
 * @id: id for the debug trace
 * @ref: reference for the debug trace
 * @mask: status bits to change
 * @set_or_clear: ZFCP_SET or ZFCP_CLEAR
 *
 * Changes in common status bits are propagated to attached ports and units.
 */
void zfcp_erp_modify_adapter_status(struct zfcp_adapter *adapter, char *id,
                                    void *ref, u32 mask, int set_or_clear)
{
        struct zfcp_port *port;
        u32 common_mask = mask & ZFCP_COMMON_FLAGS;

        if (set_or_clear == ZFCP_SET) {
                if (status_change_set(mask, &adapter->status))
                        zfcp_rec_dbf_event_adapter(id, ref, adapter);
                atomic_set_mask(mask, &adapter->status);
        } else {
                if (status_change_clear(mask, &adapter->status))
                        zfcp_rec_dbf_event_adapter(id, ref, adapter);
                atomic_clear_mask(mask, &adapter->status);
                if (mask & ZFCP_STATUS_COMMON_ERP_FAILED)
                        atomic_set(&adapter->erp_counter, 0);
        }

        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);
}

/**
 * zfcp_erp_modify_port_status - change port status bits
 * @port: port to change the status bits
 * @id: id for the debug trace
 * @ref: reference for the debug trace
 * @mask: status bits to change
 * @set_or_clear: ZFCP_SET or ZFCP_CLEAR
 *
 * Changes in common status bits are propagated to attached units.
 */
void zfcp_erp_modify_port_status(struct zfcp_port *port, char *id, void *ref,
                                 u32 mask, int set_or_clear)
{
        struct zfcp_unit *unit;
        u32 common_mask = mask & ZFCP_COMMON_FLAGS;

        if (set_or_clear == ZFCP_SET) {
                if (status_change_set(mask, &port->status))
                        zfcp_rec_dbf_event_port(id, ref, port);
                atomic_set_mask(mask, &port->status);
        } else {
                if (status_change_clear(mask, &port->status))
                        zfcp_rec_dbf_event_port(id, ref, port);
                atomic_clear_mask(mask, &port->status);
                if (mask & ZFCP_STATUS_COMMON_ERP_FAILED)
                        atomic_set(&port->erp_counter, 0);
        }

        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);
}

/**
 * zfcp_erp_modify_unit_status - change unit status bits
 * @unit: unit to change the status bits
 * @id: id for the debug trace
 * @ref: reference for the debug trace
 * @mask: status bits to change
 * @set_or_clear: ZFCP_SET or ZFCP_CLEAR
 */
void zfcp_erp_modify_unit_status(struct zfcp_unit *unit, char *id, void *ref,
                                 u32 mask, int set_or_clear)
{
        if (set_or_clear == ZFCP_SET) {
                if (status_change_set(mask, &unit->status))
                        zfcp_rec_dbf_event_unit(id, ref, unit);
                atomic_set_mask(mask, &unit->status);
        } else {
                if (status_change_clear(mask, &unit->status))
                        zfcp_rec_dbf_event_unit(id, ref, unit);
                atomic_clear_mask(mask, &unit->status);
                if (mask & ZFCP_STATUS_COMMON_ERP_FAILED) {
                        atomic_set(&unit->erp_counter, 0);
                }
        }
}

/**
 * zfcp_erp_port_boxed - Mark port as "boxed" and start ERP
 * @port: The "boxed" port.
 * @id: The debug trace id.
 * @id: Reference for the debug trace.
 */
void zfcp_erp_port_boxed(struct zfcp_port *port, char *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);
}

/**
 * zfcp_erp_unit_boxed - Mark unit as "boxed" and start ERP
 * @port: The "boxed" unit.
 * @id: The debug trace id.
 * @id: Reference for the debug trace.
 */
void zfcp_erp_unit_boxed(struct zfcp_unit *unit, char *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);
}

/**
 * zfcp_erp_port_access_denied - Adapter denied access to port.
 * @port: port where access has been denied
 * @id: id for debug trace
 * @ref: reference for debug trace
 *
 * Since the adapter has denied access, stop using the port and the
 * attached units.
 */
void zfcp_erp_port_access_denied(struct zfcp_port *port, char *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);
}

/**
 * zfcp_erp_unit_access_denied - Adapter denied access to unit.
 * @unit: unit where access has been denied
 * @id: id for debug trace
 * @ref: reference for debug trace
 *
 * Since the adapter has denied access, stop using the unit.
 */
void zfcp_erp_unit_access_denied(struct zfcp_unit *unit, char *id, void *ref)
{
        zfcp_erp_modify_unit_status(unit, id, ref,
                                    ZFCP_STATUS_COMMON_ERP_FAILED |
                                    ZFCP_STATUS_COMMON_ACCESS_DENIED, ZFCP_SET);
}

static void zfcp_erp_unit_access_changed(struct zfcp_unit *unit, char *id,
                                         void *ref)
{
        int status = atomic_read(&unit->status);
        if (!(status & (ZFCP_STATUS_COMMON_ACCESS_DENIED |
                        ZFCP_STATUS_COMMON_ACCESS_BOXED)))
                return;

        zfcp_erp_unit_reopen(unit, ZFCP_STATUS_COMMON_ERP_FAILED, id, ref);
}

static void zfcp_erp_port_access_changed(struct zfcp_port *port, char *id,
                                         void *ref)
{
        struct zfcp_unit *unit;
        int status = atomic_read(&port->status);

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

        zfcp_erp_port_reopen(port, ZFCP_STATUS_COMMON_ERP_FAILED, id, ref);
}

/**
 * zfcp_erp_adapter_access_changed - Process change in adapter ACT
 * @adapter: Adapter where the Access Control Table (ACT) changed
 * @id: Id for debug trace
 * @ref: Reference for debug trace
 */
void zfcp_erp_adapter_access_changed(struct zfcp_adapter *adapter, char *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);
        list_for_each_entry(port, &adapter->port_list_head, list)
                zfcp_erp_port_access_changed(port, id, ref);
        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
}