[SCSI] make blk layer set REQ_SOFTBARRIER on defer and requeue (2e759cd4) · Commits · 戴 / test

This is the reworked version of the patch. It sets REQ_SOFTBARRIER in two places - in elv_next_request() on BLKPREP_DEFER and in blk_requeue_request(). Signed-off-by:

Tejun Heo <htejun@gmail.com> Signed-off-by:

James Bottomley <James.Bottomley@SteelEye.com>

drivers/block/elevator.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -290,6 +290,13 @@ void elv_requeue_request(request_queue_t q, struct request rq)
		rq = rq->end_io_data;
		}

		/*
		* the request is prepped and may have some resources allocated.
		* allowing unprepped requests to pass this one may cause resource
		* deadlock. turn on softbarrier.
		*/
		rq->flags \|= REQ_SOFTBARRIER;

		/*
		* if iosched has an explicit requeue hook, then use that. otherwise
		* just put the request at the front of the queue
		@@ -386,6 +393,12 @@ struct request elv_next_request(request_queue_t q)
		if (ret == BLKPREP_OK) {
		break;
		} else if (ret == BLKPREP_DEFER) {
		/*
		* the request may have been (partially) prepped.
		* we need to keep this request in the front to
		* avoid resource deadlock. turn on softbarrier.
		*/
		rq->flags \|= REQ_SOFTBARRIER;
		rq = NULL;
		break;
		} else if (ret == BLKPREP_KILL) {

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