From 673235f915318ced5d7ec4b2bfd8cb909e6a4a55 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Wed, 2 Dec 2020 18:04:19 +0800 Subject: scsi: core: Fix race between handling STS_RESOURCE and completion When queuing I/O request to LLD, STS_RESOURCE may be returned because: - Host is in recovery or blocked - Target queue throttling or target is blocked - LLD rejection In these scenarios BLK_STS_DEV_RESOURCE is returned to the block layer to avoid an unnecessary re-run of the queue. However, all of the requests queued to this SCSI device may complete immediately after reading 'sdev->device_busy' and BLK_STS_DEV_RESOURCE is returned to block layer. In that case the current I/O won't get a chance to get queued since it is invisible at that time for both scsi_run_queue_async() and blk-mq's RESTART. Fix the issue by not returning BLK_STS_DEV_RESOURCE in this situation. Link: https://lore.kernel.org/r/20201202100419.525144-1-ming.lei@redhat.com Fixes: 86ff7c2a80cd ("blk-mq: introduce BLK_STS_DEV_RESOURCE") Cc: Hannes Reinecke Cc: Sumit Saxena Cc: Kashyap Desai Cc: Bart Van Assche Cc: Ewan Milne Cc: Long Li Reported-by: John Garry Tested-by: "chenxiang (M)" Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_lib.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/scsi') 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 @@ out_put_budget: 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: -- cgit v1.2.3