On 12/2/20 2:04 AM, Ming Lei wrote:
When queuing IO request to LLD, STS_RESOURCE may be returned because: - host in recovery or blocked - target queue throttling or blocked - LLD rejection Any one of the above doesn't happen frequently enough. BLK_STS_DEV_RESOURCE is returned to block layer for avoiding unnecessary re-run queue, and it is just one small optimization. However, all in-flight requests originated from this scsi device may be completed just after reading 'sdev->device_busy', so BLK_STS_DEV_RESOURCE is returned to block layer. And the current failed IO won't get chance to be queued any more, since it is invisible at that time for either scsi_run_queue_async() or blk-mq's RESTART. Fix the issue by not returning BLK_STS_DEV_RESOURCE in this situation. Cc: Hannes Reinecke <hare@xxxxxxxx> Cc: Sumit Saxena <sumit.saxena@xxxxxxxxxxxx> Cc: Kashyap Desai <kashyap.desai@xxxxxxxxxxxx> Cc: Bart Van Assche <bvanassche@xxxxxxx> Cc: Ewan Milne <emilne@xxxxxxxxxx> Cc: Long Li <longli@xxxxxxxxxxxxx> Tested-by: "chenxiang (M)" <chenxiang66@xxxxxxxxxxxxx> Reported-by: John Garry <john.garry@xxxxxxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- drivers/scsi/scsi_lib.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 60c7a7d74852..03c6d0620bfd 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1703,8 +1703,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, break; case BLK_STS_RESOURCE: case BLK_STS_ZONE_RESOURCE: - if (atomic_read(&sdev->device_busy) || - scsi_device_blocked(sdev)) + if (scsi_device_blocked(sdev)) ret = BLK_STS_DEV_RESOURCE; break; default:
Since this patch modifies code introduced in commit 86ff7c2a80cd ("blk-mq: introduce BLK_STS_DEV_RESOURCE"), does this patch perhaps needs a Fixes: tag?
Thanks, Bart.
