Ming Lei
673235f915
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 <hare@suse.com> Cc: Sumit Saxena <sumit.saxena@broadcom.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Ewan Milne <emilne@redhat.com> Cc: Long Li <longli@microsoft.com> Reported-by: John Garry <john.garry@huawei.com> Tested-by: "chenxiang (M)" <chenxiang66@hisilicon.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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