1 files changed, 20 insertions, 31 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 20189675677a..0916bd6d22b0 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -141,8 +141,6 @@ scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
 
 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
 {
-	struct scsi_device *sdev = cmd->device;
-
 	if (cmd->request->rq_flags & RQF_DONTPREP) {
 		cmd->request->rq_flags &= ~RQF_DONTPREP;
 		scsi_mq_uninit_cmd(cmd);
@@ -150,7 +148,6 @@ static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
 		WARN_ON_ONCE(true);
 	}
 	blk_mq_requeue_request(cmd->request, true);
-	put_device(&sdev->sdev_gendev);
 }
 
 /**
@@ -189,19 +186,7 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
 	 */
 	cmd->result = 0;
 
-	/*
-	 * Before a SCSI command is dispatched,
-	 * get_device(&sdev->sdev_gendev) is called and the host,
-	 * target and device busy counters are increased. Since
-	 * requeuing a request causes these actions to be repeated and
-	 * since scsi_device_unbusy() has already been called,
-	 * put_device(&device->sdev_gendev) must still be called. Call
-	 * put_device() after blk_mq_requeue_request() to avoid that
-	 * removal of the SCSI device can start before requeueing has
-	 * happened.
-	 */
 	blk_mq_requeue_request(cmd->request, true);
-	put_device(&device->sdev_gendev);
 }
 
 /*
@@ -585,10 +570,17 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
 	if (!blk_rq_is_scsi(req)) {
 		WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
 		cmd->flags &= ~SCMD_INITIALIZED;
-		destroy_rcu_head(&cmd->rcu);
 	}
 
 	/*
+	 * Calling rcu_barrier() is not necessary here because the
+	 * SCSI error handler guarantees that the function called by
+	 * call_rcu() has been called before scsi_end_request() is
+	 * called.
+	 */
+	destroy_rcu_head(&cmd->rcu);
+
+	/*
 	 * 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.
 	 *
@@ -612,7 +604,6 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
 		blk_mq_run_hw_queues(q, true);
 
 	percpu_ref_put(&q->q_usage_counter);
-	put_device(&sdev->sdev_gendev);
 	return false;
 }
 
@@ -1606,7 +1597,6 @@ static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
 	struct scsi_device *sdev = q->queuedata;
 
 	atomic_dec(&sdev->device_busy);
-	put_device(&sdev->sdev_gendev);
 }
 
 static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
@@ -1614,16 +1604,9 @@ static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
 	struct request_queue *q = hctx->queue;
 	struct scsi_device *sdev = q->queuedata;
 
-	if (!get_device(&sdev->sdev_gendev))
-		goto out;
-	if (!scsi_dev_queue_ready(q, sdev))
-		goto out_put_device;
-
-	return true;
+	if (scsi_dev_queue_ready(q, sdev))
+		return true;
 
-out_put_device:
-	put_device(&sdev->sdev_gendev);
-out:
 	if (atomic_read(&sdev->device_busy) == 0 && !scsi_device_blocked(sdev))
 		blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
 	return false;
@@ -1699,8 +1682,12 @@ out_put_budget:
 			ret = BLK_STS_DEV_RESOURCE;
 		break;
 	default:
+		if (unlikely(!scsi_device_online(sdev)))
+			scsi_req(req)->result = DID_NO_CONNECT << 16;
+		else
+			scsi_req(req)->result = DID_ERROR << 16;
 		/*
-		 * Make sure to release all allocated ressources when
+		 * Make sure to release all allocated resources when
 		 * we hit an error, as we will never see this command
 		 * again.
 		 */
@@ -1759,7 +1746,7 @@ static int scsi_map_queues(struct blk_mq_tag_set *set)
 
 	if (shost->hostt->map_queues)
 		return shost->hostt->map_queues(shost);
-	return blk_mq_map_queues(&set->map[0]);
+	return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
 }
 
 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
@@ -2541,8 +2528,10 @@ void scsi_device_resume(struct scsi_device *sdev)
 	 * device deleted during suspend)
 	 */
 	mutex_lock(&sdev->state_mutex);
-	sdev->quiesced_by = NULL;
-	blk_clear_pm_only(sdev->request_queue);
+	if (sdev->quiesced_by) {
+		sdev->quiesced_by = NULL;
+		blk_clear_pm_only(sdev->request_queue);
+	}
 	if (sdev->sdev_state == SDEV_QUIESCE)
 		scsi_device_set_state(sdev, SDEV_RUNNING);
 	mutex_unlock(&sdev->state_mutex);