cgroup: make ->pre_destroy() return void

[linux-2.6/libata-dev.git] / drivers / scsi / isci / task.c

/*
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * BSD LICENSE
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/completion.h>
#include <linux/irqflags.h>
#include "sas.h"
#include <scsi/libsas.h>
#include "remote_device.h"
#include "remote_node_context.h"
#include "isci.h"
#include "request.h"
#include "task.h"
#include "host.h"

/**
* isci_task_refuse() - complete the request to the upper layer driver in
*     the case where an I/O needs to be completed back in the submit path.
* @ihost: host on which the the request was queued
* @task: request to complete
* @response: response code for the completed task.
* @status: status code for the completed task.
*
*/
static void isci_task_refuse(struct isci_host *ihost, struct sas_task *task,
                             enum service_response response,
                             enum exec_status status)

{
        unsigned long flags;

        /* Normal notification (task_done) */
        dev_dbg(&ihost->pdev->dev, "%s: task = %p, response=%d, status=%d\n",
                __func__, task, response, status);

        spin_lock_irqsave(&task->task_state_lock, flags);

        task->task_status.resp = response;
        task->task_status.stat = status;

        /* Normal notification (task_done) */
        task->task_state_flags |= SAS_TASK_STATE_DONE;
        task->task_state_flags &= ~(SAS_TASK_AT_INITIATOR |
                                    SAS_TASK_STATE_PENDING);
        task->lldd_task = NULL;
        spin_unlock_irqrestore(&task->task_state_lock, flags);

        task->task_done(task);
}

#define for_each_sas_task(num, task) \
        for (; num > 0; num--,\
             task = list_entry(task->list.next, struct sas_task, list))


static inline int isci_device_io_ready(struct isci_remote_device *idev,
                                       struct sas_task *task)
{
        return idev ? test_bit(IDEV_IO_READY, &idev->flags) ||
                      (test_bit(IDEV_IO_NCQERROR, &idev->flags) &&
                       isci_task_is_ncq_recovery(task))
                    : 0;
}
/**
 * isci_task_execute_task() - This function is one of the SAS Domain Template
 *    functions. This function is called by libsas to send a task down to
 *    hardware.
 * @task: This parameter specifies the SAS task to send.
 * @num: This parameter specifies the number of tasks to queue.
 * @gfp_flags: This parameter specifies the context of this call.
 *
 * status, zero indicates success.
 */
int isci_task_execute_task(struct sas_task *task, int num, gfp_t gfp_flags)
{
        struct isci_host *ihost = dev_to_ihost(task->dev);
        struct isci_remote_device *idev;
        unsigned long flags;
        bool io_ready;
        u16 tag;

        dev_dbg(&ihost->pdev->dev, "%s: num=%d\n", __func__, num);

        for_each_sas_task(num, task) {
                enum sci_status status = SCI_FAILURE;

                spin_lock_irqsave(&ihost->scic_lock, flags);
                idev = isci_lookup_device(task->dev);
                io_ready = isci_device_io_ready(idev, task);
                tag = isci_alloc_tag(ihost);
                spin_unlock_irqrestore(&ihost->scic_lock, flags);

                dev_dbg(&ihost->pdev->dev,
                        "task: %p, num: %d dev: %p idev: %p:%#lx cmd = %p\n",
                        task, num, task->dev, idev, idev ? idev->flags : 0,
                        task->uldd_task);

                if (!idev) {
                        isci_task_refuse(ihost, task, SAS_TASK_UNDELIVERED,
                                         SAS_DEVICE_UNKNOWN);
                } else if (!io_ready || tag == SCI_CONTROLLER_INVALID_IO_TAG) {
                        /* Indicate QUEUE_FULL so that the scsi midlayer
                         * retries.
                          */
                        isci_task_refuse(ihost, task, SAS_TASK_COMPLETE,
                                         SAS_QUEUE_FULL);
                } else {
                        /* There is a device and it's ready for I/O. */
                        spin_lock_irqsave(&task->task_state_lock, flags);

                        if (task->task_state_flags & SAS_TASK_STATE_ABORTED) {
                                /* The I/O was aborted. */
                                spin_unlock_irqrestore(&task->task_state_lock,
                                                       flags);

                                isci_task_refuse(ihost, task,
                                                 SAS_TASK_UNDELIVERED,
                                                 SAM_STAT_TASK_ABORTED);
                        } else {
                                task->task_state_flags |= SAS_TASK_AT_INITIATOR;
                                spin_unlock_irqrestore(&task->task_state_lock, flags);

                                /* build and send the request. */
                                status = isci_request_execute(ihost, idev, task, tag);

                                if (status != SCI_SUCCESS) {

                                        spin_lock_irqsave(&task->task_state_lock, flags);
                                        /* Did not really start this command. */
                                        task->task_state_flags &= ~SAS_TASK_AT_INITIATOR;
                                        spin_unlock_irqrestore(&task->task_state_lock, flags);

                                        if (test_bit(IDEV_GONE, &idev->flags)) {

                                                /* Indicate that the device
                                                 * is gone.
                                                 */
                                                isci_task_refuse(ihost, task,
                                                        SAS_TASK_UNDELIVERED,
                                                        SAS_DEVICE_UNKNOWN);
                                        } else {
                                                /* Indicate QUEUE_FULL so that
                                                 * the scsi midlayer retries.
                                                 * If the request failed for
                                                 * remote device reasons, it
                                                 * gets returned as
                                                 * SAS_TASK_UNDELIVERED next
                                                 * time through.
                                                 */
                                                isci_task_refuse(ihost, task,
                                                        SAS_TASK_COMPLETE,
                                                        SAS_QUEUE_FULL);
                                        }
                                }
                        }
                }
                if (status != SCI_SUCCESS && tag != SCI_CONTROLLER_INVALID_IO_TAG) {
                        spin_lock_irqsave(&ihost->scic_lock, flags);
                        /* command never hit the device, so just free
                         * the tci and skip the sequence increment
                         */
                        isci_tci_free(ihost, ISCI_TAG_TCI(tag));
                        spin_unlock_irqrestore(&ihost->scic_lock, flags);
                }
                isci_put_device(idev);
        }
        return 0;
}

static struct isci_request *isci_task_request_build(struct isci_host *ihost,
                                                    struct isci_remote_device *idev,
                                                    u16 tag, struct isci_tmf *isci_tmf)
{
        enum sci_status status = SCI_FAILURE;
        struct isci_request *ireq = NULL;
        struct domain_device *dev;

        dev_dbg(&ihost->pdev->dev,
                "%s: isci_tmf = %p\n", __func__, isci_tmf);

        dev = idev->domain_dev;

        /* do common allocation and init of request object. */
        ireq = isci_tmf_request_from_tag(ihost, isci_tmf, tag);
        if (!ireq)
                return NULL;

        /* let the core do it's construct. */
        status = sci_task_request_construct(ihost, idev, tag,
                                             ireq);

        if (status != SCI_SUCCESS) {
                dev_warn(&ihost->pdev->dev,
                         "%s: sci_task_request_construct failed - "
                         "status = 0x%x\n",
                         __func__,
                         status);
                return NULL;
        }

        /* XXX convert to get this from task->tproto like other drivers */
        if (dev->dev_type == SAS_END_DEV) {
                isci_tmf->proto = SAS_PROTOCOL_SSP;
                status = sci_task_request_construct_ssp(ireq);
                if (status != SCI_SUCCESS)
                        return NULL;
        }

        return ireq;
}

static int isci_task_execute_tmf(struct isci_host *ihost,
                                 struct isci_remote_device *idev,
                                 struct isci_tmf *tmf, unsigned long timeout_ms)
{
        DECLARE_COMPLETION_ONSTACK(completion);
        enum sci_task_status status = SCI_TASK_FAILURE;
        struct isci_request *ireq;
        int ret = TMF_RESP_FUNC_FAILED;
        unsigned long flags;
        unsigned long timeleft;
        u16 tag;

        spin_lock_irqsave(&ihost->scic_lock, flags);
        tag = isci_alloc_tag(ihost);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        if (tag == SCI_CONTROLLER_INVALID_IO_TAG)
                return ret;

        /* sanity check, return TMF_RESP_FUNC_FAILED
         * if the device is not there and ready.
         */
        if (!idev ||
            (!test_bit(IDEV_IO_READY, &idev->flags) &&
             !test_bit(IDEV_IO_NCQERROR, &idev->flags))) {
                dev_dbg(&ihost->pdev->dev,
                        "%s: idev = %p not ready (%#lx)\n",
                        __func__,
                        idev, idev ? idev->flags : 0);
                goto err_tci;
        } else
                dev_dbg(&ihost->pdev->dev,
                        "%s: idev = %p\n",
                        __func__, idev);

        /* Assign the pointer to the TMF's completion kernel wait structure. */
        tmf->complete = &completion;
        tmf->status = SCI_FAILURE_TIMEOUT;

        ireq = isci_task_request_build(ihost, idev, tag, tmf);
        if (!ireq)
                goto err_tci;

        spin_lock_irqsave(&ihost->scic_lock, flags);

        /* start the TMF io. */
        status = sci_controller_start_task(ihost, idev, ireq);

        if (status != SCI_TASK_SUCCESS) {
                dev_dbg(&ihost->pdev->dev,
                         "%s: start_io failed - status = 0x%x, request = %p\n",
                         __func__,
                         status,
                         ireq);
                spin_unlock_irqrestore(&ihost->scic_lock, flags);
                goto err_tci;
        }
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        /* The RNC must be unsuspended before the TMF can get a response. */
        isci_remote_device_resume_from_abort(ihost, idev);

        /* Wait for the TMF to complete, or a timeout. */
        timeleft = wait_for_completion_timeout(&completion,
                                               msecs_to_jiffies(timeout_ms));

        if (timeleft == 0) {
                /* The TMF did not complete - this could be because
                 * of an unplug.  Terminate the TMF request now.
                 */
                isci_remote_device_suspend_terminate(ihost, idev, ireq);
        }

        isci_print_tmf(ihost, tmf);

        if (tmf->status == SCI_SUCCESS)
                ret =  TMF_RESP_FUNC_COMPLETE;
        else if (tmf->status == SCI_FAILURE_IO_RESPONSE_VALID) {
                dev_dbg(&ihost->pdev->dev,
                        "%s: tmf.status == "
                        "SCI_FAILURE_IO_RESPONSE_VALID\n",
                        __func__);
                ret =  TMF_RESP_FUNC_COMPLETE;
        }
        /* Else - leave the default "failed" status alone. */

        dev_dbg(&ihost->pdev->dev,
                "%s: completed request = %p\n",
                __func__,
                ireq);

        return ret;

 err_tci:
        spin_lock_irqsave(&ihost->scic_lock, flags);
        isci_tci_free(ihost, ISCI_TAG_TCI(tag));
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        return ret;
}

static void isci_task_build_tmf(struct isci_tmf *tmf,
                                enum isci_tmf_function_codes code)
{
        memset(tmf, 0, sizeof(*tmf));
        tmf->tmf_code = code;
}

static void isci_task_build_abort_task_tmf(struct isci_tmf *tmf,
                                           enum isci_tmf_function_codes code,
                                           struct isci_request *old_request)
{
        isci_task_build_tmf(tmf, code);
        tmf->io_tag = old_request->io_tag;
}

/**
 * isci_task_send_lu_reset_sas() - This function is called by of the SAS Domain
 *    Template functions.
 * @lun: This parameter specifies the lun to be reset.
 *
 * status, zero indicates success.
 */
static int isci_task_send_lu_reset_sas(
        struct isci_host *isci_host,
        struct isci_remote_device *isci_device,
        u8 *lun)
{
        struct isci_tmf tmf;
        int ret = TMF_RESP_FUNC_FAILED;

        dev_dbg(&isci_host->pdev->dev,
                "%s: isci_host = %p, isci_device = %p\n",
                __func__, isci_host, isci_device);
        /* Send the LUN reset to the target.  By the time the call returns,
         * the TMF has fully exected in the target (in which case the return
         * value is "TMF_RESP_FUNC_COMPLETE", or the request timed-out (or
         * was otherwise unable to be executed ("TMF_RESP_FUNC_FAILED").
         */
        isci_task_build_tmf(&tmf, isci_tmf_ssp_lun_reset);

        #define ISCI_LU_RESET_TIMEOUT_MS 2000 /* 2 second timeout. */
        ret = isci_task_execute_tmf(isci_host, isci_device, &tmf, ISCI_LU_RESET_TIMEOUT_MS);

        if (ret == TMF_RESP_FUNC_COMPLETE)
                dev_dbg(&isci_host->pdev->dev,
                        "%s: %p: TMF_LU_RESET passed\n",
                        __func__, isci_device);
        else
                dev_dbg(&isci_host->pdev->dev,
                        "%s: %p: TMF_LU_RESET failed (%x)\n",
                        __func__, isci_device, ret);

        return ret;
}

int isci_task_lu_reset(struct domain_device *dev, u8 *lun)
{
        struct isci_host *ihost = dev_to_ihost(dev);
        struct isci_remote_device *idev;
        unsigned long flags;
        int ret = TMF_RESP_FUNC_COMPLETE;

        spin_lock_irqsave(&ihost->scic_lock, flags);
        idev = isci_get_device(dev->lldd_dev);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        dev_dbg(&ihost->pdev->dev,
                "%s: domain_device=%p, isci_host=%p; isci_device=%p\n",
                __func__, dev, ihost, idev);

        if (!idev) {
                /* If the device is gone, escalate to I_T_Nexus_Reset. */
                dev_dbg(&ihost->pdev->dev, "%s: No dev\n", __func__);

                ret = TMF_RESP_FUNC_FAILED;
                goto out;
        }

        /* Suspend the RNC, kill all TCs */
        if (isci_remote_device_suspend_terminate(ihost, idev, NULL)
            != SCI_SUCCESS) {
                /* The suspend/terminate only fails if isci_get_device fails */
                ret = TMF_RESP_FUNC_FAILED;
                goto out;
        }
        /* All pending I/Os have been terminated and cleaned up. */
        if (!test_bit(IDEV_GONE, &idev->flags)) {
                if (dev_is_sata(dev))
                        sas_ata_schedule_reset(dev);
                else
                        /* Send the task management part of the reset. */
                        ret = isci_task_send_lu_reset_sas(ihost, idev, lun);
        }
 out:
        isci_put_device(idev);
        return ret;
}


/*       int (*lldd_clear_nexus_port)(struct asd_sas_port *); */
int isci_task_clear_nexus_port(struct asd_sas_port *port)
{
        return TMF_RESP_FUNC_FAILED;
}



int isci_task_clear_nexus_ha(struct sas_ha_struct *ha)
{
        return TMF_RESP_FUNC_FAILED;
}

/* Task Management Functions. Must be called from process context.       */

/**
 * isci_task_abort_task() - This function is one of the SAS Domain Template
 *    functions. This function is called by libsas to abort a specified task.
 * @task: This parameter specifies the SAS task to abort.
 *
 * status, zero indicates success.
 */
int isci_task_abort_task(struct sas_task *task)
{
        struct isci_host *ihost = dev_to_ihost(task->dev);
        DECLARE_COMPLETION_ONSTACK(aborted_io_completion);
        struct isci_request       *old_request = NULL;
        struct isci_remote_device *idev = NULL;
        struct isci_tmf           tmf;
        int                       ret = TMF_RESP_FUNC_FAILED;
        unsigned long             flags;

        /* Get the isci_request reference from the task.  Note that
         * this check does not depend on the pending request list
         * in the device, because tasks driving resets may land here
         * after completion in the core.
         */
        spin_lock_irqsave(&ihost->scic_lock, flags);
        spin_lock(&task->task_state_lock);

        old_request = task->lldd_task;

        /* If task is already done, the request isn't valid */
        if (!(task->task_state_flags & SAS_TASK_STATE_DONE) &&
            (task->task_state_flags & SAS_TASK_AT_INITIATOR) &&
            old_request)
                idev = isci_get_device(task->dev->lldd_dev);

        spin_unlock(&task->task_state_lock);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        dev_warn(&ihost->pdev->dev,
                 "%s: dev = %p (%s%s), task = %p, old_request == %p\n",
                 __func__, idev,
                 (dev_is_sata(task->dev) ? "STP/SATA"
                                         : ((dev_is_expander(task->dev))
                                                ? "SMP"
                                                : "SSP")),
                 ((idev) ? ((test_bit(IDEV_GONE, &idev->flags))
                           ? " IDEV_GONE"
                           : "")
                         : " <NULL>"),
                 task, old_request);

        /* Device reset conditions signalled in task_state_flags are the
         * responsbility of libsas to observe at the start of the error
         * handler thread.
         */
        if (!idev || !old_request) {
                /* The request has already completed and there
                * is nothing to do here other than to set the task
                * done bit, and indicate that the task abort function
                * was sucessful.
                */
                spin_lock_irqsave(&task->task_state_lock, flags);
                task->task_state_flags |= SAS_TASK_STATE_DONE;
                task->task_state_flags &= ~(SAS_TASK_AT_INITIATOR |
                                            SAS_TASK_STATE_PENDING);
                spin_unlock_irqrestore(&task->task_state_lock, flags);

                ret = TMF_RESP_FUNC_COMPLETE;

                dev_warn(&ihost->pdev->dev,
                         "%s: abort task not needed for %p\n",
                         __func__, task);
                goto out;
        }
        /* Suspend the RNC, kill the TC */
        if (isci_remote_device_suspend_terminate(ihost, idev, old_request)
            != SCI_SUCCESS) {
                dev_warn(&ihost->pdev->dev,
                         "%s: isci_remote_device_reset_terminate(dev=%p, "
                                 "req=%p, task=%p) failed\n",
                         __func__, idev, old_request, task);
                ret = TMF_RESP_FUNC_FAILED;
                goto out;
        }
        spin_lock_irqsave(&ihost->scic_lock, flags);

        if (task->task_proto == SAS_PROTOCOL_SMP ||
            sas_protocol_ata(task->task_proto) ||
            test_bit(IREQ_COMPLETE_IN_TARGET, &old_request->flags) ||
            test_bit(IDEV_GONE, &idev->flags)) {

                spin_unlock_irqrestore(&ihost->scic_lock, flags);

                /* No task to send, so explicitly resume the device here */
                isci_remote_device_resume_from_abort(ihost, idev);

                dev_warn(&ihost->pdev->dev,
                         "%s: %s request"
                                 " or complete_in_target (%d), "
                                 "or IDEV_GONE (%d), thus no TMF\n",
                         __func__,
                         ((task->task_proto == SAS_PROTOCOL_SMP)
                          ? "SMP"
                          : (sas_protocol_ata(task->task_proto)
                                ? "SATA/STP"
                                : "<other>")
                          ),
                         test_bit(IREQ_COMPLETE_IN_TARGET,
                                  &old_request->flags),
                         test_bit(IDEV_GONE, &idev->flags));

                spin_lock_irqsave(&task->task_state_lock, flags);
                task->task_state_flags &= ~(SAS_TASK_AT_INITIATOR |
                                            SAS_TASK_STATE_PENDING);
                task->task_state_flags |= SAS_TASK_STATE_DONE;
                spin_unlock_irqrestore(&task->task_state_lock, flags);

                ret = TMF_RESP_FUNC_COMPLETE;
        } else {
                /* Fill in the tmf stucture */
                isci_task_build_abort_task_tmf(&tmf, isci_tmf_ssp_task_abort,
                                               old_request);

                spin_unlock_irqrestore(&ihost->scic_lock, flags);

                /* Send the task management request. */
                #define ISCI_ABORT_TASK_TIMEOUT_MS 500 /* 1/2 second timeout */
                ret = isci_task_execute_tmf(ihost, idev, &tmf,
                                            ISCI_ABORT_TASK_TIMEOUT_MS);
        }
out:
        dev_warn(&ihost->pdev->dev,
                 "%s: Done; dev = %p, task = %p , old_request == %p\n",
                 __func__, idev, task, old_request);
        isci_put_device(idev);
        return ret;
}

/**
 * isci_task_abort_task_set() - This function is one of the SAS Domain Template
 *    functions. This is one of the Task Management functoins called by libsas,
 *    to abort all task for the given lun.
 * @d_device: This parameter specifies the domain device associated with this
 *    request.
 * @lun: This parameter specifies the lun associated with this request.
 *
 * status, zero indicates success.
 */
int isci_task_abort_task_set(
        struct domain_device *d_device,
        u8 *lun)
{
        return TMF_RESP_FUNC_FAILED;
}


/**
 * isci_task_clear_aca() - This function is one of the SAS Domain Template
 *    functions. This is one of the Task Management functoins called by libsas.
 * @d_device: This parameter specifies the domain device associated with this
 *    request.
 * @lun: This parameter specifies the lun        associated with this request.
 *
 * status, zero indicates success.
 */
int isci_task_clear_aca(
        struct domain_device *d_device,
        u8 *lun)
{
        return TMF_RESP_FUNC_FAILED;
}



/**
 * isci_task_clear_task_set() - This function is one of the SAS Domain Template
 *    functions. This is one of the Task Management functoins called by libsas.
 * @d_device: This parameter specifies the domain device associated with this
 *    request.
 * @lun: This parameter specifies the lun        associated with this request.
 *
 * status, zero indicates success.
 */
int isci_task_clear_task_set(
        struct domain_device *d_device,
        u8 *lun)
{
        return TMF_RESP_FUNC_FAILED;
}


/**
 * isci_task_query_task() - This function is implemented to cause libsas to
 *    correctly escalate the failed abort to a LUN or target reset (this is
 *    because sas_scsi_find_task libsas function does not correctly interpret
 *    all return codes from the abort task call).  When TMF_RESP_FUNC_SUCC is
 *    returned, libsas turns this into a LUN reset; when FUNC_FAILED is
 *    returned, libsas will turn this into a target reset
 * @task: This parameter specifies the sas task being queried.
 * @lun: This parameter specifies the lun associated with this request.
 *
 * status, zero indicates success.
 */
int isci_task_query_task(
        struct sas_task *task)
{
        /* See if there is a pending device reset for this device. */
        if (task->task_state_flags & SAS_TASK_NEED_DEV_RESET)
                return TMF_RESP_FUNC_FAILED;
        else
                return TMF_RESP_FUNC_SUCC;
}

/*
 * isci_task_request_complete() - This function is called by the sci core when
 *    an task request completes.
 * @ihost: This parameter specifies the ISCI host object
 * @ireq: This parameter is the completed isci_request object.
 * @completion_status: This parameter specifies the completion status from the
 *    sci core.
 *
 * none.
 */
void
isci_task_request_complete(struct isci_host *ihost,
                           struct isci_request *ireq,
                           enum sci_task_status completion_status)
{
        struct isci_tmf *tmf = isci_request_access_tmf(ireq);
        struct completion *tmf_complete = NULL;

        dev_dbg(&ihost->pdev->dev,
                "%s: request = %p, status=%d\n",
                __func__, ireq, completion_status);

        set_bit(IREQ_COMPLETE_IN_TARGET, &ireq->flags);

        if (tmf) {
                tmf->status = completion_status;

                if (tmf->proto == SAS_PROTOCOL_SSP) {
                        memcpy(&tmf->resp.resp_iu,
                               &ireq->ssp.rsp,
                               SSP_RESP_IU_MAX_SIZE);
                } else if (tmf->proto == SAS_PROTOCOL_SATA) {
                        memcpy(&tmf->resp.d2h_fis,
                               &ireq->stp.rsp,
                               sizeof(struct dev_to_host_fis));
                }
                /* PRINT_TMF( ((struct isci_tmf *)request->task)); */
                tmf_complete = tmf->complete;
        }
        sci_controller_complete_io(ihost, ireq->target_device, ireq);
        /* set the 'terminated' flag handle to make sure it cannot be terminated
         *  or completed again.
         */
        set_bit(IREQ_TERMINATED, &ireq->flags);

        if (test_and_clear_bit(IREQ_ABORT_PATH_ACTIVE, &ireq->flags))
                wake_up_all(&ihost->eventq);

        if (!test_bit(IREQ_NO_AUTO_FREE_TAG, &ireq->flags))
                isci_free_tag(ihost, ireq->io_tag);

        /* The task management part completes last. */
        if (tmf_complete)
                complete(tmf_complete);
}

static int isci_reset_device(struct isci_host *ihost,
                             struct domain_device *dev,
                             struct isci_remote_device *idev)
{
        int rc = TMF_RESP_FUNC_COMPLETE, reset_stat = -1;
        struct sas_phy *phy = sas_get_local_phy(dev);
        struct isci_port *iport = dev->port->lldd_port;

        dev_dbg(&ihost->pdev->dev, "%s: idev %p\n", __func__, idev);

        /* Suspend the RNC, terminate all outstanding TCs. */
        if (isci_remote_device_suspend_terminate(ihost, idev, NULL)
            != SCI_SUCCESS) {
                rc = TMF_RESP_FUNC_FAILED;
                goto out;
        }
        /* Note that since the termination for outstanding requests succeeded,
         * this function will return success.  This is because the resets will
         * only fail if the device has been removed (ie. hotplug), and the
         * primary duty of this function is to cleanup tasks, so that is the
         * relevant status.
         */
        if (!test_bit(IDEV_GONE, &idev->flags)) {
                if (scsi_is_sas_phy_local(phy)) {
                        struct isci_phy *iphy = &ihost->phys[phy->number];

                        reset_stat = isci_port_perform_hard_reset(ihost, iport,
                                                                  iphy);
                } else
                        reset_stat = sas_phy_reset(phy, !dev_is_sata(dev));
        }
        /* Explicitly resume the RNC here, since there was no task sent. */
        isci_remote_device_resume_from_abort(ihost, idev);

        dev_dbg(&ihost->pdev->dev, "%s: idev %p complete, reset_stat=%d.\n",
                __func__, idev, reset_stat);
 out:
        sas_put_local_phy(phy);
        return rc;
}

int isci_task_I_T_nexus_reset(struct domain_device *dev)
{
        struct isci_host *ihost = dev_to_ihost(dev);
        struct isci_remote_device *idev;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&ihost->scic_lock, flags);
        idev = isci_get_device(dev->lldd_dev);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        if (!idev) {
                /* XXX: need to cleanup any ireqs targeting this
                 * domain_device
                 */
                ret = TMF_RESP_FUNC_COMPLETE;
                goto out;
        }

        ret = isci_reset_device(ihost, dev, idev);
 out:
        isci_put_device(idev);
        return ret;
}