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Message-ID: <YueS04RIq2gTUGgg@kroah.com>
Date: Mon, 1 Aug 2022 10:46:11 +0200
From: Greg KH <greg@...ah.com>
To: Yu Kuai <yukuai1@...weicloud.com>
Cc: ming.lei@...hat.com, stable@...r.kernel.org, jejb@...ux.ibm.com,
martin.petersen@...cle.com, linux-scsi@...r.kernel.org,
linux-kernel@...r.kernel.org, yukuai3@...wei.com,
yi.zhang@...wei.com
Subject: Re: [PATCH stable 5.4] scsi: core: Fix race between handling
STS_RESOURCE and completion
On Mon, Aug 01, 2022 at 09:22:51AM +0800, Yu Kuai wrote:
> From: Ming Lei <ming.lei@...hat.com>
>
> 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 <hare@...e.com>
> Cc: Sumit Saxena <sumit.saxena@...adcom.com>
> Cc: Kashyap Desai <kashyap.desai@...adcom.com>
> Cc: Bart Van Assche <bvanassche@....org>
> Cc: Ewan Milne <emilne@...hat.com>
> Cc: Long Li <longli@...rosoft.com>
> Reported-by: John Garry <john.garry@...wei.com>
> Tested-by: "chenxiang (M)" <chenxiang66@...ilicon.com>
> Signed-off-by: Ming Lei <ming.lei@...hat.com>
> Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> ---
> drivers/scsi/scsi_lib.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
Both now queued up, thanks.
greg k-h
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