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. Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Reviewed-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Cc: Can Guo <cang@xxxxxxxxxxxxxx> Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx> Cc: Ming Lei <ming.lei@xxxxxxxxxx> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> --- drivers/scsi/scsi_error.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index d94449188270..6de6e1bf3dcb 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -1993,7 +1993,12 @@ static void scsi_eh_lock_door(struct scsi_device *sdev) struct request *req; struct scsi_request *rq; - req = blk_get_request(sdev->request_queue, REQ_OP_SCSI_IN, 0); + /* + * It is not guaranteed that a request is available nor that + * sdev->request_queue is unfrozen. Hence the BLK_MQ_REQ_NOWAIT below. + */ + req = blk_get_request(sdev->request_queue, REQ_OP_SCSI_IN, + BLK_MQ_REQ_NOWAIT); if (IS_ERR(req)) return; rq = scsi_req(req);
