/*
- * scsi_lib.c Copyright (C) 1999 Eric Youngdale
+ * Copyright (C) 1999 Eric Youngdale
+ * Copyright (C) 2014 Christoph Hellwig
*
* SCSI queueing library.
* Initial versions: Eric Youngdale (eric@andante.org).
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <linux/scatterlist.h>
+#include <linux/blk-mq.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
}
}
+static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+ struct request_queue *q = cmd->request->q;
+
+ blk_mq_requeue_request(cmd->request);
+ blk_mq_kick_requeue_list(q);
+ put_device(&sdev->sdev_gendev);
+}
+
/**
* __scsi_queue_insert - private queue insertion
* @cmd: The SCSI command being requeued
* 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);
atomic_dec(&sdev->device_busy);
}
+static void scsi_kick_queue(struct request_queue *q)
+{
+ if (q->mq_ops)
+ blk_mq_start_hw_queues(q);
+ else
+ blk_run_queue(q);
+}
+
/*
* 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 -
* but in most cases, we will be first. Ideally, each LU on the
* target would get some limited time or requests on the target.
*/
- blk_run_queue(current_sdev->request_queue);
+ scsi_kick_queue(current_sdev->request_queue);
spin_lock_irqsave(shost->host_lock, flags);
if (starget->starget_sdev_user)
continue;
spin_unlock_irqrestore(shost->host_lock, flags);
- blk_run_queue(sdev->request_queue);
+ scsi_kick_queue(sdev->request_queue);
spin_lock_irqsave(shost->host_lock, flags);
scsi_device_put(sdev);
continue;
spin_unlock_irqrestore(shost->host_lock, flags);
- blk_run_queue(slq);
+ scsi_kick_queue(slq);
blk_put_queue(slq);
spin_lock_irqsave(shost->host_lock, flags);
if (!list_empty(&sdev->host->starved_list))
scsi_starved_list_run(sdev->host);
- blk_run_queue(q);
+ if (q->mq_ops)
+ blk_mq_start_stopped_hw_queues(q, false);
+ else
+ blk_run_queue(q);
}
void scsi_requeue_run_queue(struct work_struct *work)
return mempool_alloc(sgp->pool, gfp_mask);
}
-static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
+static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
{
- __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, false, scsi_sg_free);
+ if (mq && sdb->table.nents <= SCSI_MAX_SG_SEGMENTS)
+ return;
+ __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
}
static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
- gfp_t gfp_mask)
+ gfp_t gfp_mask, bool mq)
{
+ struct scatterlist *first_chunk = NULL;
int ret;
BUG_ON(!nents);
+ if (mq) {
+ if (nents <= SCSI_MAX_SG_SEGMENTS) {
+ sdb->table.nents = nents;
+ sg_init_table(sdb->table.sgl, sdb->table.nents);
+ return 0;
+ }
+ first_chunk = sdb->table.sgl;
+ }
+
ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
- NULL, gfp_mask, scsi_sg_alloc);
+ first_chunk, gfp_mask, scsi_sg_alloc);
if (unlikely(ret))
- scsi_free_sgtable(sdb);
+ scsi_free_sgtable(sdb, mq);
return ret;
}
+static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
+{
+ if (cmd->request->cmd_type == REQ_TYPE_FS) {
+ struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
+
+ if (drv->uninit_command)
+ drv->uninit_command(cmd);
+ }
+}
+
+static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
+{
+ if (cmd->sdb.table.nents)
+ scsi_free_sgtable(&cmd->sdb, true);
+ if (cmd->request->next_rq && cmd->request->next_rq->special)
+ scsi_free_sgtable(cmd->request->next_rq->special, true);
+ if (scsi_prot_sg_count(cmd))
+ scsi_free_sgtable(cmd->prot_sdb, true);
+}
+
+static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+ unsigned long flags;
+
+ BUG_ON(list_empty(&cmd->list));
+
+ scsi_mq_free_sgtables(cmd);
+ scsi_uninit_cmd(cmd);
+
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_del_init(&cmd->list);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+}
+
/*
* Function: scsi_release_buffers()
*
static void scsi_release_buffers(struct scsi_cmnd *cmd)
{
if (cmd->sdb.table.nents)
- scsi_free_sgtable(&cmd->sdb);
+ scsi_free_sgtable(&cmd->sdb, false);
memset(&cmd->sdb, 0, sizeof(cmd->sdb));
if (scsi_prot_sg_count(cmd))
- scsi_free_sgtable(cmd->prot_sdb);
+ scsi_free_sgtable(cmd->prot_sdb, false);
}
static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
{
struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
- scsi_free_sgtable(bidi_sdb);
+ scsi_free_sgtable(bidi_sdb, false);
kmem_cache_free(scsi_sdb_cache, bidi_sdb);
cmd->request->next_rq->special = NULL;
}
struct scsi_cmnd *cmd = req->special;
struct scsi_device *sdev = cmd->device;
struct request_queue *q = sdev->request_queue;
- unsigned long flags;
-
if (blk_update_request(req, error, bytes))
return true;
if (blk_queue_add_random(q))
add_disk_randomness(req->rq_disk);
- spin_lock_irqsave(q->queue_lock, flags);
- blk_finish_request(req, error);
- spin_unlock_irqrestore(q->queue_lock, flags);
+ if (req->mq_ctx) {
+ /*
+ * In the MQ case the command gets freed by __blk_mq_end_io,
+ * 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_io(req, error);
+
+ if (scsi_target(sdev)->single_lun ||
+ !list_empty(&sdev->host->starved_list))
+ kblockd_schedule_work(&sdev->requeue_work);
+ else
+ blk_mq_start_stopped_hw_queues(q, true);
+
+ put_device(&sdev->sdev_gendev);
+ } else {
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_finish_request(req, error);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ if (bidi_bytes)
+ scsi_release_bidi_buffers(cmd);
+ scsi_release_buffers(cmd);
+ scsi_next_command(cmd);
+ }
- if (bidi_bytes)
- scsi_release_bidi_buffers(cmd);
- scsi_release_buffers(cmd);
- scsi_next_command(cmd);
return false;
}
/* Unprep the request and put it back at the head of the queue.
* A new command will be prepared and issued.
*/
- scsi_release_buffers(cmd);
- scsi_requeue_command(q, cmd);
+ if (q->mq_ops) {
+ cmd->request->cmd_flags &= ~REQ_DONTPREP;
+ scsi_mq_uninit_cmd(cmd);
+ scsi_mq_requeue_cmd(cmd);
+ } else {
+ scsi_release_buffers(cmd);
+ scsi_requeue_command(q, cmd);
+ }
break;
case ACTION_RETRY:
/* Retry the same command immediately */
* If sg table allocation fails, requeue request later.
*/
if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
- gfp_mask))) {
+ gfp_mask, req->mq_ctx != NULL)))
return BLKPREP_DEFER;
- }
/*
* Next, walk the list, and fill in the addresses and sizes of
{
struct scsi_device *sdev = cmd->device;
struct request *rq = cmd->request;
+ bool is_mq = (rq->mq_ctx != NULL);
int error;
BUG_ON(!rq->nr_phys_segments);
goto err_exit;
if (blk_bidi_rq(rq)) {
- struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
- scsi_sdb_cache, GFP_ATOMIC);
- if (!bidi_sdb) {
- error = BLKPREP_DEFER;
- goto err_exit;
+ if (!rq->q->mq_ops) {
+ struct scsi_data_buffer *bidi_sdb =
+ kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
+ if (!bidi_sdb) {
+ error = BLKPREP_DEFER;
+ goto err_exit;
+ }
+
+ rq->next_rq->special = bidi_sdb;
}
- rq->next_rq->special = bidi_sdb;
- error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
+ error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special,
+ GFP_ATOMIC);
if (error)
goto err_exit;
}
BUG_ON(prot_sdb == NULL);
ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
- if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
+ if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask, is_mq)) {
error = BLKPREP_DEFER;
goto err_exit;
}
cmd->prot_sdb->table.nents = count;
}
- return BLKPREP_OK ;
-
+ return BLKPREP_OK;
err_exit:
- scsi_release_buffers(cmd);
- cmd->request->special = NULL;
- scsi_put_command(cmd);
- put_device(&sdev->sdev_gendev);
+ if (is_mq) {
+ scsi_mq_free_sgtables(cmd);
+ } else {
+ scsi_release_buffers(cmd);
+ cmd->request->special = NULL;
+ scsi_put_command(cmd);
+ put_device(&sdev->sdev_gendev);
+ }
return error;
}
EXPORT_SYMBOL(scsi_init_io);
static void scsi_unprep_fn(struct request_queue *q, struct request *req)
{
- if (req->cmd_type == REQ_TYPE_FS) {
- struct scsi_cmnd *cmd = req->special;
- struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
-
- if (drv->uninit_command)
- drv->uninit_command(cmd);
- }
+ scsi_uninit_cmd(req->special);
}
/*
* unblock after device_blocked iterates to zero
*/
if (atomic_dec_return(&sdev->device_blocked) > 0) {
- blk_delay_queue(q, SCSI_QUEUE_DELAY);
+ /*
+ * For the MQ case we take care of this in the caller.
+ */
+ if (!q->mq_ops)
+ blk_delay_queue(q, SCSI_QUEUE_DELAY);
goto out_dec;
}
SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
blk_delay_queue(q, SCSI_QUEUE_DELAY);
}
+static inline int prep_to_mq(int ret)
+{
+ switch (ret) {
+ case BLKPREP_OK:
+ return 0;
+ case BLKPREP_DEFER:
+ return BLK_MQ_RQ_QUEUE_BUSY;
+ default:
+ return BLK_MQ_RQ_QUEUE_ERROR;
+ }
+}
+
+static int scsi_mq_prep_fn(struct request *req)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+ struct scsi_device *sdev = req->q->queuedata;
+ struct Scsi_Host *shost = sdev->host;
+ unsigned char *sense_buf = cmd->sense_buffer;
+ struct scatterlist *sg;
+
+ memset(cmd, 0, sizeof(struct scsi_cmnd));
+
+ req->special = cmd;
+
+ cmd->request = req;
+ cmd->device = sdev;
+ cmd->sense_buffer = sense_buf;
+
+ cmd->tag = req->tag;
+
+ req->cmd = req->__cmd;
+ cmd->cmnd = req->cmd;
+ cmd->prot_op = SCSI_PROT_NORMAL;
+
+ INIT_LIST_HEAD(&cmd->list);
+ INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
+ cmd->jiffies_at_alloc = jiffies;
+
+ /*
+ * XXX: cmd_list lookups are only used by two drivers, try to get
+ * rid of this list in common code.
+ */
+ spin_lock_irq(&sdev->list_lock);
+ list_add_tail(&cmd->list, &sdev->cmd_list);
+ spin_unlock_irq(&sdev->list_lock);
+
+ sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
+ cmd->sdb.table.sgl = sg;
+
+ if (scsi_host_get_prot(shost)) {
+ cmd->prot_sdb = (void *)sg +
+ shost->sg_tablesize * sizeof(struct scatterlist);
+ memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
+
+ cmd->prot_sdb->table.sgl =
+ (struct scatterlist *)(cmd->prot_sdb + 1);
+ }
+
+ if (blk_bidi_rq(req)) {
+ struct request *next_rq = req->next_rq;
+ struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
+
+ memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
+ bidi_sdb->table.sgl =
+ (struct scatterlist *)(bidi_sdb + 1);
+
+ next_rq->special = bidi_sdb;
+ }
+
+ return scsi_setup_cmnd(sdev, req);
+}
+
+static void scsi_mq_done(struct scsi_cmnd *cmd)
+{
+ trace_scsi_dispatch_cmd_done(cmd);
+ blk_mq_complete_request(cmd->request);
+}
+
+static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
+{
+ struct request_queue *q = req->q;
+ struct scsi_device *sdev = q->queuedata;
+ struct Scsi_Host *shost = sdev->host;
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+ int ret;
+ int reason;
+
+ ret = prep_to_mq(scsi_prep_state_check(sdev, req));
+ if (ret)
+ goto out;
+
+ ret = BLK_MQ_RQ_QUEUE_BUSY;
+ if (!get_device(&sdev->sdev_gendev))
+ goto out;
+
+ if (!scsi_dev_queue_ready(q, sdev))
+ goto out_put_device;
+ if (!scsi_target_queue_ready(shost, sdev))
+ goto out_dec_device_busy;
+ if (!scsi_host_queue_ready(q, shost, sdev))
+ goto out_dec_target_busy;
+
+ if (!(req->cmd_flags & REQ_DONTPREP)) {
+ ret = prep_to_mq(scsi_mq_prep_fn(req));
+ if (ret)
+ goto out_dec_host_busy;
+ req->cmd_flags |= REQ_DONTPREP;
+ }
+
+ scsi_init_cmd_errh(cmd);
+ cmd->scsi_done = scsi_mq_done;
+
+ reason = scsi_dispatch_cmd(cmd);
+ if (reason) {
+ scsi_set_blocked(cmd, reason);
+ ret = BLK_MQ_RQ_QUEUE_BUSY;
+ goto out_dec_host_busy;
+ }
+
+ return BLK_MQ_RQ_QUEUE_OK;
+
+out_dec_host_busy:
+ atomic_dec(&shost->host_busy);
+out_dec_target_busy:
+ if (scsi_target(sdev)->can_queue > 0)
+ atomic_dec(&scsi_target(sdev)->target_busy);
+out_dec_device_busy:
+ atomic_dec(&sdev->device_busy);
+out_put_device:
+ put_device(&sdev->sdev_gendev);
+out:
+ switch (ret) {
+ case BLK_MQ_RQ_QUEUE_BUSY:
+ blk_mq_stop_hw_queue(hctx);
+ if (atomic_read(&sdev->device_busy) == 0 &&
+ !scsi_device_blocked(sdev))
+ blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
+ break;
+ case BLK_MQ_RQ_QUEUE_ERROR:
+ /*
+ * Make sure to release all allocated ressources when
+ * we hit an error, as we will never see this command
+ * again.
+ */
+ if (req->cmd_flags & REQ_DONTPREP)
+ scsi_mq_uninit_cmd(cmd);
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+static int scsi_init_request(void *data, struct request *rq,
+ unsigned int hctx_idx, unsigned int request_idx,
+ unsigned int numa_node)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+
+ cmd->sense_buffer = kzalloc_node(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL,
+ numa_node);
+ if (!cmd->sense_buffer)
+ return -ENOMEM;
+ return 0;
+}
+
+static void scsi_exit_request(void *data, struct request *rq,
+ unsigned int hctx_idx, unsigned int request_idx)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+
+ kfree(cmd->sense_buffer);
+}
+
static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
{
struct device *host_dev;
return bounce_limit;
}
-struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
- request_fn_proc *request_fn)
+static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
{
- struct request_queue *q;
struct device *dev = shost->dma_dev;
- q = blk_init_queue(request_fn, NULL);
- if (!q)
- return NULL;
-
/*
* this limit is imposed by hardware restrictions
*/
* blk_queue_update_dma_alignment() later.
*/
blk_queue_dma_alignment(q, 0x03);
+}
+struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
+ request_fn_proc *request_fn)
+{
+ struct request_queue *q;
+
+ q = blk_init_queue(request_fn, NULL);
+ if (!q)
+ return NULL;
+ __scsi_init_queue(shost, q);
return q;
}
EXPORT_SYMBOL(__scsi_alloc_queue);
return q;
}
+static struct blk_mq_ops scsi_mq_ops = {
+ .map_queue = blk_mq_map_queue,
+ .queue_rq = scsi_queue_rq,
+ .complete = scsi_softirq_done,
+ .timeout = scsi_times_out,
+ .init_request = scsi_init_request,
+ .exit_request = scsi_exit_request,
+};
+
+struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
+{
+ sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
+ if (IS_ERR(sdev->request_queue))
+ return NULL;
+
+ sdev->request_queue->queuedata = sdev;
+ __scsi_init_queue(sdev->host, sdev->request_queue);
+ return sdev->request_queue;
+}
+
+int scsi_mq_setup_tags(struct Scsi_Host *shost)
+{
+ unsigned int cmd_size, sgl_size, tbl_size;
+
+ tbl_size = shost->sg_tablesize;
+ if (tbl_size > SCSI_MAX_SG_SEGMENTS)
+ tbl_size = SCSI_MAX_SG_SEGMENTS;
+ sgl_size = tbl_size * sizeof(struct scatterlist);
+ cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
+ if (scsi_host_get_prot(shost))
+ cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
+
+ memset(&shost->tag_set, 0, sizeof(shost->tag_set));
+ shost->tag_set.ops = &scsi_mq_ops;
+ shost->tag_set.nr_hw_queues = 1;
+ shost->tag_set.queue_depth = shost->can_queue;
+ shost->tag_set.cmd_size = cmd_size;
+ shost->tag_set.numa_node = NUMA_NO_NODE;
+ shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ shost->tag_set.driver_data = shost;
+
+ return blk_mq_alloc_tag_set(&shost->tag_set);
+}
+
+void scsi_mq_destroy_tags(struct Scsi_Host *shost)
+{
+ blk_mq_free_tag_set(&shost->tag_set);
+}
+
/*
* Function: scsi_block_requests()
*
* block layer from calling the midlayer with this device's
* request queue.
*/
- spin_lock_irqsave(q->queue_lock, flags);
- blk_stop_queue(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
+ if (q->mq_ops) {
+ blk_mq_stop_hw_queues(q);
+ } else {
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_stop_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
return 0;
}
sdev->sdev_state != SDEV_OFFLINE)
return -EINVAL;
- spin_lock_irqsave(q->queue_lock, flags);
- blk_start_queue(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
+ if (q->mq_ops) {
+ blk_mq_start_stopped_hw_queues(q, false);
+ } else {
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_start_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
return 0;
}
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