Release 4.11 drivers/scsi/scsi_lib.c

/*
 * Copyright (C) 1999 Eric Youngdale
 * Copyright (C) 2014 Christoph Hellwig
 *
 *  SCSI queueing library.
 *      Initial versions: Eric Youngdale (eric@andante.org).
 *                        Based upon conversations with large numbers
 *                        of people at Linux Expo.
 */

#include <linux/bio.h>
#include <linux/bitops.h>
#include <linux/blkdev.h>
#include <linux/completion.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <linux/scatterlist.h>
#include <linux/blk-mq.h>
#include <linux/ratelimit.h>
#include <asm/unaligned.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_dh.h>

#include <trace/events/scsi.h>

#include "scsi_priv.h"
#include "scsi_logging.h"


static struct kmem_cache *scsi_sdb_cache;

static struct kmem_cache *scsi_sense_cache;

static struct kmem_cache *scsi_sense_isadma_cache;
static DEFINE_MUTEX(scsi_sense_cache_mutex);


static inline struct kmem_cache *

scsi_select_sense_cache(struct Scsi_Host *shost)
{
	return shost->unchecked_isa_dma ?
		scsi_sense_isadma_cache : scsi_sense_cache;
}

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static void scsi_free_sense_buffer(struct Scsi_Host *shost,
		unsigned char *sense_buffer)
{
	kmem_cache_free(scsi_select_sense_cache(shost), sense_buffer);
}

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static unsigned char *scsi_alloc_sense_buffer(struct Scsi_Host *shost,
	gfp_t gfp_mask, int numa_node)
{
	return kmem_cache_alloc_node(scsi_select_sense_cache(shost), gfp_mask,
			numa_node);
}

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int scsi_init_sense_cache(struct Scsi_Host *shost)
{
	struct kmem_cache *cache;
	int ret = 0;

	cache = scsi_select_sense_cache(shost);
	if (cache)
		return 0;

	mutex_lock(&scsi_sense_cache_mutex);
	if (shost->unchecked_isa_dma) {
		scsi_sense_isadma_cache =
			kmem_cache_create("scsi_sense_cache(DMA)",
			SCSI_SENSE_BUFFERSIZE, 0,
			SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
		if (!scsi_sense_isadma_cache)
			ret = -ENOMEM;
	} else {
		scsi_sense_cache =
			kmem_cache_create("scsi_sense_cache",
			SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN, NULL);
		if (!scsi_sense_cache)
			ret = -ENOMEM;
	}

	mutex_unlock(&scsi_sense_cache_mutex);
	return ret;
}

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/*
 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
 * not change behaviour from the previous unplug mechanism, experimentation
 * may prove this needs changing.
 */

#define SCSI_QUEUE_DELAY	3


static void

scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
{
	struct Scsi_Host *host = cmd->device->host;
	struct scsi_device *device = cmd->device;
	struct scsi_target *starget = scsi_target(device);

	/*
         * Set the appropriate busy bit for the device/host.
         *
         * If the host/device isn't busy, assume that something actually
         * completed, and that we should be able to queue a command now.
         *
         * Note that the prior mid-layer assumption that any host could
         * always queue at least one command is now broken.  The mid-layer
         * will implement a user specifiable stall (see
         * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
         * if a command is requeued with no other commands outstanding
         * either for the device or for the host.
         */
	switch (reason) {
	case SCSI_MLQUEUE_HOST_BUSY:
		atomic_set(&host->host_blocked, host->max_host_blocked);
		break;
	case SCSI_MLQUEUE_DEVICE_BUSY:
	case SCSI_MLQUEUE_EH_RETRY:
		atomic_set(&device->device_blocked,
			   device->max_device_blocked);
		break;
	case SCSI_MLQUEUE_TARGET_BUSY:
		atomic_set(&starget->target_blocked,
			   starget->max_target_blocked);
		break;
	}
}

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Christoph Hellwig
63
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4
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Mike Christie
30
29.41%
1
8.33%
James Smart
3
2.94%
1
8.33%
Tejun Heo
2
1.96%
2
16.67%
Linus Torvalds
1
0.98%
1
8.33%
Mike Anderson
1
0.98%
1
8.33%
James Bottomley
1
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1
8.33%
Bart Van Assche
1
0.98%
1
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102
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12
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static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
{
	struct scsi_device *sdev = cmd->device;

	blk_mq_requeue_request(cmd->request, true);
	put_device(&sdev->sdev_gendev);
}

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35
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2
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/**
 * __scsi_queue_insert - private queue insertion
 * @cmd: The SCSI command being requeued
 * @reason:  The reason for the requeue
 * @unbusy: Whether the queue should be unbusied
 *
 * This is a private queue insertion.  The public interface
 * scsi_queue_insert() always assumes the queue should be unbusied
 * because it's always called before the completion.  This function is
 * for a requeue after completion, which should only occur in this
 * file.
 */


static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
{
	struct scsi_device *device = cmd->device;
	struct request_queue *q = device->request_queue;
	unsigned long flags;

	SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
		"Inserting command %p into mlqueue\n", cmd));

	scsi_set_blocked(cmd, reason);

	/*
         * Decrement the counters, since these commands are no longer
         * active on the host/device.
         */
	if (unbusy)
		scsi_device_unbusy(device);

	/*
         * Requeue this command.  It will go before all other commands
         * that are already in the queue. Schedule requeue work under
         * lock such that the kblockd_schedule_work() call happens
         * before blk_cleanup_queue() finishes.
         */
	cmd->result = 0;
	if (q->mq_ops) {
		scsi_mq_requeue_cmd(cmd);
		return;
	}
	spin_lock_irqsave(q->queue_lock, flags);
	blk_requeue_request(q, cmd->request);
	kblockd_schedule_work(&device->requeue_work);
	spin_unlock_irqrestore(q->queue_lock, flags);
}

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80
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4
30.77%
Tejun Heo
13
10.16%
1
7.69%
Bart Van Assche
10
7.81%
1
7.69%
James Bottomley
7
5.47%
2
15.38%
Alan Stern
6
4.69%
1
7.69%
Jens Axboe
5
3.91%
1
7.69%
Linus Torvalds
4
3.12%
1
7.69%
Patrick Mansfield
2
1.56%
1
7.69%
Linus Torvalds (pre-git)
1
0.78%
1
7.69%
Total
128
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13
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/*
 * Function:    scsi_queue_insert()
 *
 * Purpose:     Insert a command in the midlevel queue.
 *
 * Arguments:   cmd    - command that we are adding to queue.
 *              reason - why we are inserting command to queue.
 *
 * Lock status: Assumed that lock is not held upon entry.
 *
 * Returns:     Nothing.
 *
 * Notes:       We do this for one of two cases.  Either the host is busy
 *              and it cannot accept any more commands for the time being,
 *              or the device returned QUEUE_FULL and can accept no more
 *              commands.
 * Notes:       This could be called either from an interrupt context or a
 *              normal process context.
 */


void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
{
	__scsi_queue_insert(cmd, reason, 1);
}


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/**
 * scsi_execute - insert request and wait for the result
 * @sdev:       scsi device
 * @cmd:        scsi command
 * @data_direction: data direction
 * @buffer:     data buffer
 * @bufflen:    len of buffer
 * @sense:      optional sense buffer
 * @sshdr:      optional decoded sense header
 * @timeout:    request timeout in seconds
 * @retries:    number of times to retry request
 * @flags:      flags for ->cmd_flags
 * @rq_flags:   flags for ->rq_flags
 * @resid:      optional residual length
 *
 * returns the req->errors value which is the scsi_cmnd result
 * field.
 */


int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
		 int data_direction, void *buffer, unsigned bufflen,
		 unsigned char *sense, struct scsi_sense_hdr *sshdr,
		 int timeout, int retries, u64 flags, req_flags_t rq_flags,
		 int *resid)
{
	struct request *req;
	struct scsi_request *rq;
	int ret = DRIVER_ERROR << 24;

	req = blk_get_request(sdev->request_queue,
			data_direction == DMA_TO_DEVICE ?
			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, __GFP_RECLAIM);
	if (IS_ERR(req))
		return ret;
	rq = scsi_req(req);
	scsi_req_init(req);

	if (bufflen &&	blk_rq_map_kern(sdev->request_queue, req,
					buffer, bufflen, __GFP_RECLAIM))
		goto out;

	rq->cmd_len = COMMAND_SIZE(cmd[0]);
	memcpy(rq->cmd, cmd, rq->cmd_len);
	req->retries = retries;
	req->timeout = timeout;
	req->cmd_flags |= flags;
	req->rq_flags |= rq_flags | RQF_QUIET | RQF_PREEMPT;

	/*
         * head injection *required* here otherwise quiesce won't work
         */
	blk_execute_rq(req->q, NULL, req, 1);

	/*
         * Some devices (USB mass-storage in particular) may transfer
         * garbage data together with a residue indicating that the data
         * is invalid.  Prevent the garbage from being misinterpreted
         * and prevent security leaks by zeroing out the excess data.
         */
	if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
		memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);

	if (resid)
		*resid = rq->resid_len;
	if (sense && rq->sense_len)
		memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
	if (sshdr)
		scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
	ret = req->errors;
 out:
	blk_put_request(req);

	return ret;
}
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80
26.76%
5
29.41%
Alan Stern
29
9.70%
1
5.88%
FUJITA Tomonori
13
4.35%
1
5.88%
Mike Christie
6
2.01%
1
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Jens Axboe
6
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2
11.76%
Tejun Heo
5
1.67%
1
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Joe Lawrence
3
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Mel Gorman
2
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1
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Martin K. Petersen
1
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EXPORT_SYMBOL(scsi_execute);

/*
 * Function:    scsi_init_cmd_errh()
 *
 * Purpose:     Initialize cmd fields related to error handling.
 *
 * Arguments:   cmd     - command that is ready to be queued.
 *
 * Notes:       This function has the job of initializing a number of
 *              fields related to error handling.   Typically this will
 *              be called once for each command, as required.
 */


static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
{
	cmd->serial_number = 0;
	scsi_set_resid(cmd, 0);
	memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
	if (cmd->cmd_len == 0)
		cmd->cmd_len = scsi_command_size(cmd->cmnd);
}

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Linus Torvalds (pre-git)
34
62.96%
1
11.11%
Christoph Hellwig
10
18.52%
3
33.33%
Boaz Harrosh
5
9.26%
2
22.22%
Michael Reed
3
5.56%
1
11.11%
Alan Cox
1
1.85%
1
11.11%
FUJITA Tomonori
1
1.85%
1
11.11%
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54
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9
100.00%



void scsi_device_unbusy(struct scsi_device *sdev)
{
	struct Scsi_Host *shost = sdev->host;
	struct scsi_target *starget = scsi_target(sdev);
	unsigned long flags;

	atomic_dec(&shost->host_busy);
	if (starget->can_queue > 0)
		atomic_dec(&starget->target_busy);

	if (unlikely(scsi_host_in_recovery(shost) &&
		     (shost->host_failed || shost->host_eh_scheduled))) {
		spin_lock_irqsave(shost->host_lock, flags);
		scsi_eh_wakeup(shost);
		spin_unlock_irqrestore(shost->host_lock, flags);
	}

	atomic_dec(&sdev->device_busy);
}

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Christoph Hellwig
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14
12.73%
1
12.50%
Tejun Heo
6
5.45%
1
12.50%
James Bottomley
3
2.73%
1
12.50%
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110
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8
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static void scsi_kick_queue(struct request_queue *q)
{
	if (q->mq_ops)
		blk_mq_start_hw_queues(q);
	else
		blk_run_queue(q);
}

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/*
 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
 * and call blk_run_queue for all the scsi_devices on the target -
 * including current_sdev first.
 *
 * Called with *no* scsi locks held.
 */


static void scsi_single_lun_run(struct scsi_device *current_sdev)
{
	struct Scsi_Host *shost = current_sdev->host;
	struct scsi_device *sdev, *tmp;
	struct scsi_target *starget = scsi_target(current_sdev);
	unsigned long flags;

	spin_lock_irqsave(shost->host_lock, flags);
	starget->starget_sdev_user = NULL;
	spin_unlock_irqrestore(shost->host_lock, flags);

	/*
         * Call blk_run_queue for all LUNs on the target, starting with
         * current_sdev. We race with others (to set starget_sdev_user),
         * but in most cases, we will be first. Ideally, each LU on the
         * target would get some limited time or requests on the target.
         */
	scsi_kick_queue(current_sdev->request_queue);

	spin_lock_irqsave(shost->host_lock, flags);
	if (starget->starget_sdev_user)
		goto out;
	list_for_each_entry_safe(sdev, tmp, &starget->devices,
			same_target_siblings) {
		if (sdev == current_sdev)
			continue;
		if (scsi_device_get(sdev))
			continue;

		spin_unlock_irqrestore(shost->host_lock, flags);
		scsi_kick_queue(sdev->request_queue);
		spin_lock_irqsave(shost->host_lock, flags);
	
		scsi_device_put(sdev);
	}
 out:
	spin_unlock_irqrestore(shost->host_lock, flags);
}

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57
35.62%
3
37.50%
James Bottomley
20
12.50%
1
12.50%
Linus Torvalds
1
0.62%
1
12.50%
Total
160
100.00%
8
100.00%



static inline bool scsi_device_is_busy(struct scsi_device *sdev)
{
	if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
		return true;
	if (atomic_read(&sdev->device_blocked) > 0)
		return true;
	return false;
}

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19
40.43%
2
66.67%
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47
100.00%
3
100.00%



static inline bool scsi_target_is_busy(struct scsi_target *starget)
{
	if (starget->can_queue > 0) {
		if (atomic_read(&starget->target_busy) >= starget->can_queue)
			return true;
		if (atomic_read(&starget->target_blocked) > 0)
			return true;
	}
	return false;
}

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47.37%
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4
100.00%



static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
{
	if (shost->can_queue > 0 &&
	    atomic_read(&shost->host_busy) >= shost->can_queue)
		return true;
	if (atomic_read(&shost->host_blocked) > 0)
		return true;
	if (shost->host_self_blocked)
		return true;
	return false;
}

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37
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33.33%
Christoph Hellwig
25
40.32%
2
66.67%
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62
100.00%
3
100.00%



static void scsi_starved_list_run(struct Scsi_Host *shost)
{
	LIST_HEAD(starved_list);
	struct scsi_device *sdev;
	unsigned long flags;

	spin_lock_irqsave(shost->host_lock, flags);
	list_splice_init(&shost->starved_list, &starved_list);

	while (!list_empty(&starved_list)) {
		struct request_queue *slq;

		/*
                 * As long as shost is accepting commands and we have
                 * starved queues, call blk_run_queue. scsi_request_fn
                 * drops the queue_lock and can add us back to the
                 * starved_list.
                 *
                 * host_lock protects the starved_list and starved_entry.
                 * scsi_request_fn must get the host_lock before checking
                 * or modifying starved_list or starved_entry.
                 */
		if (scsi_host_is_busy(shost))
			break;

		sdev = list_entry(starved_list.next,
				  struct scsi_device, starved_entry);
		list_del_init(&sdev->starved_entry);
		if (scsi_target_is_busy(scsi_target(sdev))) {
			list_move_tail(&sdev->starved_entry,
				       &shost->starved_list);
			continue;
		}

		/*
                 * Once we drop the host lock, a racing scsi_remove_device()
                 * call may remove the sdev from the starved list and destroy
                 * it and the queue.  Mitigate by taking a reference to the
                 * queue and never touching the sdev again after we drop the
                 * host lock.  Note: if __scsi_remove_device() invokes
                 * blk_cleanup_queue() before the queue is run from this
                 * function then blk_run_queue() will return immediately since
                 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
                 */
		slq = sdev->request_queue;
		if (!blk_get_queue(slq))
			continue;
		spin_unlock_irqrestore(shost->host_lock, flags);

		scsi_kick_queue(slq);
		blk_put_queue(slq);

		spin_lock_irqsave(shost->host_lock, flags);
	}
	/* put any unprocessed entries back */
	list_splice(&starved_list, &shost->starved_list);
	spin_unlock_irqrestore(shost->host_lock, flags);
}

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11.76%
Patrick Mansfield
31
16.94%
3
17.65%
James Bottomley
30
16.39%
1
5.88%
Christoph Hellwig
21
11.48%
5
29.41%
Jens Axboe
13
7.10%
1
5.88%
Doug Ledford
10
5.46%
2
11.76%
Linus Torvalds (pre-git)
7
3.83%
2
11.76%
Kiyoshi Ueda
2
1.09%
1
5.88%
Total
183
100.00%
17
100.00%

/*
 * Function:   scsi_run_queue()
 *
 * Purpose:    Select a proper request queue to serve next
 *
 * Arguments:  q       - last request's queue
 *
 * Returns:     Nothing
 *
 * Notes:      The previous command was completely finished, start
 *             a new one if possible.
 */


static void scsi_run_queue(struct request_queue *q)
{
	struct scsi_device *sdev = q->queuedata;

	if (scsi_target(sdev)->single_lun)
		scsi_single_lun_run(sdev);
	if (!list_empty(&sdev->host->starved_list))
		scsi_starved_list_run(sdev->host);

	if (q->mq_ops)
		blk_mq_run_hw_queues(q, false);
	else
		blk_run_queue(q);
}

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Christoph Hellwig
67
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4
5.48%
1
16.67%
Bart Van Assche
1
1.37%
1
16.67%
Linus Torvalds
1
1.37%
1
16.67%
Total
73
100.00%
6
100.00%



void scsi_requeue_run_queue(struct work_struct *work)
{
	struct scsi_device *sdev;
	struct request_queue *q;

	sdev = container_of(work, struct scsi_device, requeue_work);
	q = sdev->request_queue;
	scsi_run_queue(q);
}

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100.00%
1
100.00%
Total
43
100.00%
1
100.00%

/*
 * Function:    scsi_requeue_command()
 *
 * Purpose:     Handle post-processing of completed commands.
 *
 * Arguments:   q       - queue to operate on
 *              cmd     - command that may need to be requeued.
 *
 * Returns:     Nothing
 *
 * Notes:       After command completion, there may be blocks left
 *              over which weren't finished by the previous command
 *              this can be for a number of reasons - the main one is
 *              I/O errors in the middle of the request, in which case
 *              we need to request the blocks that come after the bad
 *              sector.
 * Notes:       Upon return, cmd is a stale pointer.
 */


static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
{
	struct scsi_device *sdev = cmd->device;
	struct request *req = cmd->request;
	unsigned long flags;

	spin_lock_irqsave(q->queue_lock, flags);
	blk_unprep_request(req);
	req->special = NULL;
	scsi_put_command(cmd);
	blk_requeue_request(q, req);
	spin_unlock_irqrestore(q->queue_lock, flags);

	scsi_run_queue(q);

	put_device(&sdev->sdev_gendev);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
44
47.83%
2
28.57%
Bart Van Assche
17
18.48%
1
14.29%
Tejun Heo
16
17.39%
1
14.29%
James Bottomley
15
16.30%
3
42.86%
Total
92
100.00%
7
100.00%



void scsi_run_host_queues(struct Scsi_Host *shost)
{
	struct scsi_device *sdev;

	shost_for_each_device(sdev, shost)
		scsi_run_queue(sdev->request_queue);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
28
100.00%
2
100.00%
Total
28
100.00%
2
100.00%



static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
{
	if (!blk_rq_is_passthrough(cmd->request)) {
		struct scsi_driver *drv = scsi_cmd_to_driver(cmd);

		if (drv->uninit_command)
			drv->uninit_command(cmd);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
33
71.74%
5
62.50%
Linus Torvalds (pre-git)
8
17.39%
1
12.50%
Boaz Harrosh
5
10.87%
2
25.00%
Total
46
100.00%
8
100.00%



static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
{
	struct scsi_data_buffer *sdb;

	if (cmd->sdb.table.nents)
		sg_free_table_chained(&cmd->sdb.table, true);
	if (cmd->request->next_rq) {
		sdb = cmd->request->next_rq->special;
		if (sdb)
			sg_free_table_chained(&sdb->table, true);
	}
	if (scsi_prot_sg_count(cmd))
		sg_free_table_chained(&cmd->prot_sdb->table, true);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
63
69.23%
2
40.00%
Ming Lin
25
27.47%
2
40.00%
Boaz Harrosh
3
3.30%
1
20.00%
Total
91
100.00%
5
100.00%



static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
{
	struct scsi_device *sdev = cmd->device;
	struct Scsi_Host *shost = sdev->host;
	unsigned long flags;

	scsi_mq_free_sgtables(cmd);
	scsi_uninit_cmd(cmd);

	if (shost->use_cmd_list) {
		BUG_ON(list_empty(&cmd->list));
		spin_lock_irqsave(&sdev->list_lock, flags);
		list_del_init(&cmd->list);
		spin_unlock_irqrestore(&sdev->list_lock, flags);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
64
71.11%
1
50.00%
Kashyap Desai
26
28.89%
1
50.00%
Total
90
100.00%
2
100.00%

/*
 * Function:    scsi_release_buffers()
 *
 * Purpose:     Free resources allocate for a scsi_command.
 *
 * Arguments:   cmd     - command that we are bailing.
 *
 * Lock status: Assumed that no lock is held upon entry.
 *
 * Returns:     Nothing
 *
 * Notes:       In the event that an upper level driver rejects a
 *              command, we must release resources allocated during
 *              the __init_io() function.  Primarily this would involve
 *              the scatter-gather table.
 */


static void scsi_release_buffers(struct scsi_cmnd *cmd)
{
	if (cmd->sdb.table.nents)
		sg_free_table_chained(&cmd->sdb.table, false);

	memset(&cmd->sdb, 0, sizeof(cmd->sdb));

	if (scsi_prot_sg_count(cmd))
		sg_free_table_chained(&cmd->prot_sdb->table, false);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
62
89.86%
1
33.33%
Ming Lin
7
10.14%
2
66.67%
Total
69
100.00%
3
100.00%



static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
{
	struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;

	sg_free_table_chained(&bidi_sdb->table, false);
	kmem_cache_free(scsi_sdb_cache, bidi_sdb);
	cmd->request->next_rq->special = NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
28
54.90%
1
20.00%
Boaz Harrosh
18
35.29%
1
20.00%
Ming Lin
4
7.84%
2
40.00%
Martin K. Petersen
1
1.96%
1
20.00%
Total
51
100.00%
5
100.00%



static bool scsi_end_request(struct request *req, int error,
		unsigned int bytes, unsigned int bidi_bytes)
{
	struct scsi_cmnd *cmd = req->special;
	struct scsi_device *sdev = cmd->device;
	struct request_queue *q = sdev->request_queue;

	if (blk_update_request(req, error, bytes))
		return true;

	/* Bidi request must be completed as a whole */
	if (unlikely(bidi_bytes) &&
	    blk_update_request(req->next_rq, error, bidi_bytes))
		return true;

	if (blk_queue_add_random(q))
		add_disk_randomness(req->rq_disk);

	if (req->mq_ctx) {
		/*
                 * In the MQ case the command gets freed by __blk_mq_end_request,
                 * so we have to do all cleanup that depends on it earlier.
                 *
                 * We also can't kick the queues from irq context, so we
                 * will have to defer it to a workqueue.
                 */
		scsi_mq_uninit_cmd(cmd);

		__blk_mq_end_request(req, error);

		if (scsi_target(sdev)->single_lun ||
		    !list_empty(&sdev->host->starved_list))
			kblockd_schedule_work(&sdev->requeue_work);
		else
			blk_mq_run_hw_queues(q, true);
	} else {
		unsigned long flags;

		if (bidi_bytes)
			scsi_release_bidi_buffers(cmd);
		scsi_release_buffers(cmd);
		scsi_put_command(cmd);

		spin_lock_irqsave(q->queue_lock, flags);
		blk_finish_request(req, error);
		spin_unlock_irqrestore(q->queue_lock, flags);

		scsi_run_queue(q);
	}

	put_device(&sdev->sdev_gendev);
	return false;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
213
95.52%
5
71.43%
Daniel Gryniewicz
9
4.04%
1
14.29%
Bart Van Assche
1
0.45%
1
14.29%
Total
223
100.00%
7
100.00%

/**
 * __scsi_error_from_host_byte - translate SCSI error code into errno
 * @cmd:        SCSI command (unused)
 * @result:     scsi error code
 *
 * Translate SCSI error code into standard UNIX errno.
 * Return values:
 * -ENOLINK     temporary transport failure
 * -EREMOTEIO   permanent target failure, do not retry
 * -EBADE       permanent nexus failure, retry on other path
 * -ENOSPC      No write space available
 * -ENODATA     Medium error
 * -EIO         unspecified I/O error
 */


static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
{
	int error = 0;

	switch(host_byte(result)) {
	case DID_TRANSPORT_FAILFAST:
		error = -ENOLINK;
		break;
	case DID_TARGET_FAILURE:
		set_host_byte(cmd, DID_OK);
		error = -EREMOTEIO;
		break;
	case DID_NEXUS_FAILURE:
		set_host_byte(cmd, DID_OK);
		error = -EBADE;
		break;
	case DID_ALLOC_FAILURE:
		set_host_byte(cmd, DID_OK);
		error = -ENOSPC;
		break;
	case DID_MEDIUM_ERROR:
		set_host_byte(cmd, DID_OK);
		error = -ENODATA;
		break;
	default:
		error = -EIO;
		break;
	}

	return error;
}

Contributors
Person
Tokens
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CommitProp
Hannes Reinecke
103
92.79%
3
75.00%
Babu Moger
8
7.21%
1
25.00%
Total
111
100.00%
4
100.00%

/*
 * Function:    scsi_io_completion()
 *
 * Purpose:     Completion processing for block device I/O requests.
 *
 * Arguments:   cmd   - command that is finished.
 *
 * Lock status: Assumed that no lock is held upon entry.
 *
 * Returns:     Nothing
 *
 * Notes:       We will finish off the specified number of sectors.  If we
 *              are done, the command block will be released and the queue
 *              function will be goosed.  If we are not done then we have to
 *              figure out what to do next:
 *
 *              a) We can call scsi_requeue_command().  The request
 *                 will be unprepared and put back on the queue.  Then
 *                 a new command will be created for it.  This should
 *                 be used if we made forward progress, or if we want
 *                 to switch from READ(10) to READ(6) for example.
 *
 *              b) We can call __scsi_queue_insert().  The request will
 *                 be put back on the queue and retried using the same
 *                 command as before, possibly after a delay.
 *
 *              c) We can call scsi_end_request() with -EIO to fail
 *                 the remainder of the request.
 */


void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
{
	int result = cmd->result;
	struct request_queue *q = cmd->device->request_queue;
	struct request *req = cmd->request;
	int error = 0;
	struct scsi_sense_hdr sshdr;
	bool sense_valid = false;
	int sense_deferred = 0, level = 0;
	enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
	      ACTION_DELAYED_RETRY} action;
	unsigned long wait_for = (cmd->allowed + 1) * req->timeout;

	if (result) {
		sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
		if (sense_valid)
			sense_deferred = scsi_sense_is_deferred(&sshdr);
	}

	if (blk_rq_is_passthrough(req)) {
		if (result) {
			if (sense_valid) {
				/*
                                 * SG_IO wants current and deferred errors
                                 */
				scsi_req(req)->sense_len =
					min(8 + cmd->sense_buffer[7],
					    SCSI_SENSE_BUFFERSIZE);
			}
			if (!sense_deferred)
				error = __scsi_error_from_host_byte(cmd, result);
		}
		/*
                 * __scsi_error_from_host_byte may have reset the host_byte
                 */
		req->errors = cmd->result;

		scsi_req(req)->resid_len = scsi_get_resid(cmd);

		if (scsi_bidi_cmnd(cmd)) {
			/*
                         * Bidi commands Must be complete as a whole,
                         * both sides at once.
                         */
			scsi_req(req->next_rq)->resid_len = scsi_in(cmd)->resid;
			if (scsi_end_request(req, 0, blk_rq_bytes(req),
					blk_rq_bytes(req->next_rq)))
				BUG();
			return;
		}
	} else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
		/*
                 * Flush commands do not transfers any data, and thus cannot use
                 * good_bytes != blk_rq_bytes(req) as the signal for an error.
                 * This sets the error explicitly for the problem case.
                 */
		error = __scsi_error_from_host_byte(cmd, result);
	}

	/* no bidi support for !blk_rq_is_passthrough yet */
	BUG_ON(blk_bidi_rq(req));

	/*
         * Next deal with any sectors which we were able to correctly
         * handle.
         */
	SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
		"%u sectors total, %d bytes done.\n",
		blk_rq_sectors(req), good_bytes));

	/*
         * Recovered errors need reporting, but they're always treated as
         * success, so fiddle the result code here.  For passthrough requests
         * we already took a copy of the original into rq->errors which
         * is what gets returned to the user
         */
	if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
		/* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
                 * print since caller wants ATA registers. Only occurs on
                 * SCSI ATA PASS_THROUGH commands when CK_COND=1
                 */
		if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
			;
		else if (!(req->rq_flags & RQF_QUIET))
			scsi_print_sense(cmd);
		result = 0;
		/* for passthrough error may be set */
		error = 0;