1 files changed, 25 insertions, 1 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index cf5b99e1f12b..887045ae5d10 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1120,7 +1120,8 @@ int scsi_init_io(struct scsi_cmnd *cmd)
         bool is_mq = (rq->mq_ctx != NULL);
         int error;
 
-        BUG_ON(!rq->nr_phys_segments);
+        if (WARN_ON_ONCE(!rq->nr_phys_segments))
+                return -EINVAL;
 
         error = scsi_init_sgtable(rq, &cmd->sdb);
         if (error)
@@ -2214,6 +2215,29 @@ void scsi_mq_destroy_tags(struct Scsi_Host *shost)
         blk_mq_free_tag_set(&shost->tag_set);
 }
 
+/**
+ * scsi_device_from_queue - return sdev associated with a request_queue
+ * @q: The request queue to return the sdev from
+ *
+ * Return the sdev associated with a request queue or NULL if the
+ * request_queue does not reference a SCSI device.
+ */
+struct scsi_device *scsi_device_from_queue(struct request_queue *q)
+{
+        struct scsi_device *sdev = NULL;
+
+        if (q->mq_ops) {
+                if (q->mq_ops == &scsi_mq_ops)
+                        sdev = q->queuedata;
+        } else if (q->request_fn == scsi_request_fn)
+                sdev = q->queuedata;
+        if (!sdev || !get_device(&sdev->sdev_gendev))
+                sdev = NULL;
+
+        return sdev;
+}
+EXPORT_SYMBOL_GPL(scsi_device_from_queue);
+
 /*
  * Function:    scsi_block_requests()
  *