From: Ming Lei Date: Wed, 2 Dec 2020 10:04:19 +0000 (+0800) Subject: scsi: core: Fix race between handling STS_RESOURCE and completion X-Git-Tag: v5.4.209~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0b0088e475870cfc36a0762354bf224d8a1041aa;p=thirdparty%2Fkernel%2Fstable.git scsi: core: Fix race between handling STS_RESOURCE and completion commit 673235f915318ced5d7ec4b2bfd8cb909e6a4a55 upstream. 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 Signed-off-by: Yu Kuai Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 8e6d7ba95df14..98e363d0025b4 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1719,8 +1719,7 @@ out_put_budget: case BLK_STS_OK: break; case BLK_STS_RESOURCE: - if (atomic_read(&sdev->device_busy) || - scsi_device_blocked(sdev)) + if (scsi_device_blocked(sdev)) ret = BLK_STS_DEV_RESOURCE; break; default: