Small core patch to fix a corner case bug: we forgot to run the queues
to handle starvation in the error exit from the scsi_queue_rq routine,
which can lead to hangs on error conditions.
The patch is available here:
git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git scsi-fixes
The short changelog is:
Ming Lei (1):
scsi: core: Run queue in case of I/O resource contention failure
And the diffstat:
drivers/scsi/scsi_lib.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
With full diff below.
James
---
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0ba7a65e7c8d..06056e9ec333 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -547,6 +547,15 @@ static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
scsi_uninit_cmd(cmd);
}
+static void scsi_run_queue_async(struct scsi_device *sdev)
+{
+ if (scsi_target(sdev)->single_lun ||
+ !list_empty(&sdev->host->starved_list))
+ kblockd_schedule_work(&sdev->requeue_work);
+ else
+ blk_mq_run_hw_queues(sdev->request_queue, true);
+}
+
/* Returns false when no more bytes to process, true if there are more */
static bool scsi_end_request(struct request *req, blk_status_t error,
unsigned int bytes)
@@ -591,11 +600,7 @@ static bool scsi_end_request(struct request *req,
blk_status_t error,
__blk_mq_end_request(req, error);
- if (scsi_target(sdev)->single_lun ||
- !list_empty(&sdev->host->starved_list))
- kblockd_schedule_work(&sdev->requeue_work);
- else
- blk_mq_run_hw_queues(q, true);
+ scsi_run_queue_async(sdev);
percpu_ref_put(&q->q_usage_counter);
return false;
@@ -1702,6 +1707,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx
*hctx,
*/
if (req->rq_flags & RQF_DONTPREP)
scsi_mq_uninit_cmd(cmd);
+ scsi_run_queue_async(sdev);
break;
}
return ret;
