1 files changed, 87 insertions, 32 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index c289991ffaed..532304d42f00 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -294,7 +294,8 @@ void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
 	if (starget->can_queue > 0)
 		atomic_dec(&starget->target_busy);
 
-	atomic_dec(&sdev->device_busy);
+	sbitmap_put(&sdev->budget_map, cmd->budget_token);
+	cmd->budget_token = -1;
 }
 
 static void scsi_kick_queue(struct request_queue *q)
@@ -350,7 +351,7 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev)
 
 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
 {
-	if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
+	if (scsi_device_busy(sdev) >= sdev->queue_depth)
 		return true;
 	if (atomic_read(&sdev->device_blocked) > 0)
 		return true;
@@ -964,8 +965,11 @@ static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
 }
 
 /**
- * scsi_alloc_sgtables - allocate S/G tables for a command
- * @cmd:  command descriptor we wish to initialize
+ * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
+ * @cmd: SCSI command data structure to initialize.
+ *
+ * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
+ * for @cmd.
  *
  * Returns:
  * * BLK_STS_OK       - on success
@@ -1109,6 +1113,7 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
 	unsigned long jiffies_at_alloc;
 	int retries, to_clear;
 	bool in_flight;
+	int budget_token = cmd->budget_token;
 
 	if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
 		flags |= SCMD_INITIALIZED;
@@ -1137,6 +1142,7 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
 	cmd->retries = retries;
 	if (in_flight)
 		__set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
+	cmd->budget_token = budget_token;
 
 }
 
@@ -1220,19 +1226,20 @@ scsi_device_state_check(struct scsi_device *sdev, struct request *req)
 }
 
 /*
- * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
- * return 0.
- *
- * Called with the queue_lock held.
+ * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
+ * and return the token else return -1.
  */
 static inline int scsi_dev_queue_ready(struct request_queue *q,
 				  struct scsi_device *sdev)
 {
-	unsigned int busy;
+	int token;
 
-	busy = atomic_inc_return(&sdev->device_busy) - 1;
+	token = sbitmap_get(&sdev->budget_map);
 	if (atomic_read(&sdev->device_blocked)) {
-		if (busy)
+		if (token < 0)
+			goto out;
+
+		if (scsi_device_busy(sdev) > 1)
 			goto out_dec;
 
 		/*
@@ -1244,13 +1251,12 @@ static inline int scsi_dev_queue_ready(struct request_queue *q,
 				   "unblocking device at zero depth\n"));
 	}
 
-	if (busy >= sdev->queue_depth)
-		goto out_dec;
-
-	return 1;
+	return token;
 out_dec:
-	atomic_dec(&sdev->device_busy);
-	return 0;
+	if (token >= 0)
+		sbitmap_put(&sdev->budget_map, token);
+out:
+	return -1;
 }
 
 /*
@@ -1394,10 +1400,14 @@ static bool scsi_mq_lld_busy(struct request_queue *q)
 	return false;
 }
 
-static void scsi_softirq_done(struct request *rq)
+/*
+ * Block layer request completion callback. May be called from interrupt
+ * context.
+ */
+static void scsi_complete(struct request *rq)
 {
 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
-	int disposition;
+	enum scsi_disposition disposition;
 
 	INIT_LIST_HEAD(&cmd->eh_entry);
 
@@ -1571,19 +1581,20 @@ static void scsi_mq_done(struct scsi_cmnd *cmd)
 	blk_mq_complete_request(cmd->request);
 }
 
-static void scsi_mq_put_budget(struct request_queue *q)
+static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
 {
 	struct scsi_device *sdev = q->queuedata;
 
-	atomic_dec(&sdev->device_busy);
+	sbitmap_put(&sdev->budget_map, budget_token);
 }
 
-static bool scsi_mq_get_budget(struct request_queue *q)
+static int scsi_mq_get_budget(struct request_queue *q)
 {
 	struct scsi_device *sdev = q->queuedata;
+	int token = scsi_dev_queue_ready(q, sdev);
 
-	if (scsi_dev_queue_ready(q, sdev))
-		return true;
+	if (token >= 0)
+		return token;
 
 	atomic_inc(&sdev->restarts);
 
@@ -1602,10 +1613,24 @@ static bool scsi_mq_get_budget(struct request_queue *q)
 	 * the .restarts flag, and the request queue will be run for handling
 	 * this request, see scsi_end_request().
 	 */
-	if (unlikely(atomic_read(&sdev->device_busy) == 0 &&
+	if (unlikely(scsi_device_busy(sdev) == 0 &&
 				!scsi_device_blocked(sdev)))
 		blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
-	return false;
+	return -1;
+}
+
+static void scsi_mq_set_rq_budget_token(struct request *req, int token)
+{
+	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+
+	cmd->budget_token = token;
+}
+
+static int scsi_mq_get_rq_budget_token(struct request *req)
+{
+	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+
+	return cmd->budget_token;
 }
 
 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
@@ -1619,6 +1644,8 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	blk_status_t ret;
 	int reason;
 
+	WARN_ON_ONCE(cmd->budget_token < 0);
+
 	/*
 	 * If the device is not in running state we will reject some or all
 	 * commands.
@@ -1670,7 +1697,8 @@ out_dec_target_busy:
 	if (scsi_target(sdev)->can_queue > 0)
 		atomic_dec(&scsi_target(sdev)->target_busy);
 out_put_budget:
-	scsi_mq_put_budget(q);
+	scsi_mq_put_budget(q, cmd->budget_token);
+	cmd->budget_token = -1;
 	switch (ret) {
 	case BLK_STS_OK:
 		break;
@@ -1750,6 +1778,26 @@ static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
 	kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
 }
 
+
+static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx)
+{
+	struct Scsi_Host *shost = hctx->driver_data;
+
+	if (shost->hostt->mq_poll)
+		return shost->hostt->mq_poll(shost, hctx->queue_num);
+
+	return 0;
+}
+
+static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
+			  unsigned int hctx_idx)
+{
+	struct Scsi_Host *shost = data;
+
+	hctx->driver_data = shost;
+	return 0;
+}
+
 static int scsi_map_queues(struct blk_mq_tag_set *set)
 {
 	struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
@@ -1804,7 +1852,7 @@ static const struct blk_mq_ops scsi_mq_ops_no_commit = {
 	.get_budget	= scsi_mq_get_budget,
 	.put_budget	= scsi_mq_put_budget,
 	.queue_rq	= scsi_queue_rq,
-	.complete	= scsi_softirq_done,
+	.complete	= scsi_complete,
 	.timeout	= scsi_timeout,
 #ifdef CONFIG_BLK_DEBUG_FS
 	.show_rq	= scsi_show_rq,
@@ -1815,14 +1863,16 @@ static const struct blk_mq_ops scsi_mq_ops_no_commit = {
 	.cleanup_rq	= scsi_cleanup_rq,
 	.busy		= scsi_mq_lld_busy,
 	.map_queues	= scsi_map_queues,
+	.init_hctx	= scsi_init_hctx,
+	.poll		= scsi_mq_poll,
+	.set_rq_budget_token = scsi_mq_set_rq_budget_token,
+	.get_rq_budget_token = scsi_mq_get_rq_budget_token,
 };
 
 
 static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
 {
-	struct request_queue *q = hctx->queue;
-	struct scsi_device *sdev = q->queuedata;
-	struct Scsi_Host *shost = sdev->host;
+	struct Scsi_Host *shost = hctx->driver_data;
 
 	shost->hostt->commit_rqs(shost, hctx->queue_num);
 }
@@ -1832,7 +1882,7 @@ static const struct blk_mq_ops scsi_mq_ops = {
 	.put_budget	= scsi_mq_put_budget,
 	.queue_rq	= scsi_queue_rq,
 	.commit_rqs	= scsi_commit_rqs,
-	.complete	= scsi_softirq_done,
+	.complete	= scsi_complete,
 	.timeout	= scsi_timeout,
 #ifdef CONFIG_BLK_DEBUG_FS
 	.show_rq	= scsi_show_rq,
@@ -1843,6 +1893,10 @@ static const struct blk_mq_ops scsi_mq_ops = {
 	.cleanup_rq	= scsi_cleanup_rq,
 	.busy		= scsi_mq_lld_busy,
 	.map_queues	= scsi_map_queues,
+	.init_hctx	= scsi_init_hctx,
+	.poll		= scsi_mq_poll,
+	.set_rq_budget_token = scsi_mq_set_rq_budget_token,
+	.get_rq_budget_token = scsi_mq_get_rq_budget_token,
 };
 
 struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
@@ -1875,6 +1929,7 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
 	else
 		tag_set->ops = &scsi_mq_ops_no_commit;
 	tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
+	tag_set->nr_maps = shost->nr_maps ? : 1;
 	tag_set->queue_depth = shost->can_queue;
 	tag_set->cmd_size = cmd_size;
 	tag_set->numa_node = NUMA_NO_NODE;