1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 88d1b5f44e5..fe77ccacf31 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1497,6 +1497,21 @@ static void scsi_request_fn(struct request_queue *q)
                 }
                 spin_lock(shost->host_lock);
 
+                /*
+                 * We hit this when the driver is using a host wide
+                 * tag map. For device level tag maps the queue_depth check
+                 * in the device ready fn would prevent us from trying
+                 * to allocate a tag. Since the map is a shared host resource
+                 * we add the dev to the starved list so it eventually gets
+                 * a run when a tag is freed.
+                 */
+                if (blk_queue_tagged(q) && (req->tag == -1)) {
+                        if (list_empty(&sdev->starved_entry))
+                                list_add_tail(&sdev->starved_entry,
+                                              &shost->starved_list);
+                        goto not_ready;
+                }
+
                 if (!scsi_host_queue_ready(q, shost, sdev))
                         goto not_ready;
                 if (scsi_target(sdev)->single_lun) {