block: Introduce BLK_MQ_REQ_PREEMPT

Set RQF_PREEMPT if BLK_MQ_REQ_PREEMPT is passed to blk_get_request_flags(). Signed-off-by: Bart Van Assche <[email protected]> Reviewed-by: Hannes Reinecke <[email protected]> Tested-by: Martin Steigerwald <[email protected]> Tested-by: Oleksandr Natalenko <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Ming Lei <[email protected]> Cc: Johannes Thumshirn <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
olifre · Nov 11, 2017 · 1b6d65a · 1b6d65a
1 parent 6a15674
commit 1b6d65a
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Showing 3 changed files with 6 additions and 1 deletion.
diff --git a/block/blk-core.c b/block/blk-core.c
@@ -1263,6 +1263,8 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
 	blk_rq_set_rl(rq, rl);
 	rq->cmd_flags = op;
 	rq->rq_flags = rq_flags;
+	if (flags & BLK_MQ_REQ_PREEMPT)
+		rq->rq_flags |= RQF_PREEMPT;
 
 	/* init elvpriv */
 	if (rq_flags & RQF_ELVPRIV) {
@@ -1444,7 +1446,7 @@ struct request *blk_get_request_flags(struct request_queue *q, unsigned int op,
 	struct request *req;
 
 	WARN_ON_ONCE(op & REQ_NOWAIT);
-	WARN_ON_ONCE(flags & ~BLK_MQ_REQ_NOWAIT);
+	WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PREEMPT));
 
 	if (q->mq_ops) {
 		req = blk_mq_alloc_request(q, op, flags);

diff --git a/block/blk-mq.c b/block/blk-mq.c
@@ -291,6 +291,8 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
 	rq->q = data->q;
 	rq->mq_ctx = data->ctx;
 	rq->cmd_flags = op;
+	if (data->flags & BLK_MQ_REQ_PREEMPT)
+		rq->rq_flags |= RQF_PREEMPT;
 	if (blk_queue_io_stat(data->q))
 		rq->rq_flags |= RQF_IO_STAT;
 	/* do not touch atomic flags, it needs atomic ops against the timer */

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
@@ -212,6 +212,7 @@ enum {
 	BLK_MQ_REQ_NOWAIT	= (1 << 0), /* return when out of requests */
 	BLK_MQ_REQ_RESERVED	= (1 << 1), /* allocate from reserved pool */
 	BLK_MQ_REQ_INTERNAL	= (1 << 2), /* allocate internal/sched tag */
+	BLK_MQ_REQ_PREEMPT	= (1 << 3), /* set RQF_PREEMPT */
 };
 
 struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,