On Sun, Nov 15, 2020 at 07:04:55PM -0800, Bart Van Assche wrote:

scsi_eh_lock_door() is the only function in the SCSI error handler that
calls blk_get_request(). It is not guaranteed that a request is available
when scsi_eh_lock_door() is called. Hence pass the BLK_MQ_REQ_NOWAIT flag
to blk_get_request(). This patch has a second purpose, namely preventing
that scsi_eh_lock_door() deadlocks if sdev->request_queue is frozen and if
a SCSI command is submitted to a SCSI device through a second request
queue that has not been frozen. A later patch will namely modify the SPI
DV code such that sdev->requeust_queue is frozen during domain validation.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>