@@ -2478,6 +2478,51 @@ static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
return BLK_MAX_REQUEST_COUNT;
}
+static struct request *blk_mq_get_new_requests(struct request_queue *q,
+ struct blk_plug *plug,
+ struct bio *bio)
+{
+ struct blk_mq_alloc_data data = {
+ .q = q,
+ .nr_tags = 1,
+ .cmd_flags = bio->bi_opf,
+ };
+ struct request *rq;
+
+ if (plug) {
+ data.nr_tags = plug->nr_ios;
+ plug->nr_ios = 1;
+ data.cached_rq = &plug->cached_rq;
+ }
+
+ rq = __blk_mq_alloc_requests(&data);
+ if (rq)
+ return rq;
+
+ rq_qos_cleanup(q, bio);
+ if (bio->bi_opf & REQ_NOWAIT)
+ bio_wouldblock_error(bio);
+ return NULL;
+}
+
+static inline struct request *blk_mq_get_request(struct request_queue *q,
+ struct blk_plug *plug,
+ struct bio *bio)
+{
+ if (plug) {
+ struct request *rq;
+
+ rq = rq_list_peek(&plug->cached_rq);
+ if (rq) {
+ plug->cached_rq = rq_list_next(rq);
+ INIT_LIST_HEAD(&rq->queuelist);
+ return rq;
+ }
+ }
+
+ return blk_mq_get_new_requests(q, plug, bio);
+}
+
/**
* blk_mq_submit_bio - Create and send a request to block device.
* @bio: Bio pointer.
@@ -2518,29 +2563,9 @@ void blk_mq_submit_bio(struct bio *bio)
rq_qos_throttle(q, bio);
plug = blk_mq_plug(q, bio);
- if (plug && plug->cached_rq) {
- rq = rq_list_pop(&plug->cached_rq);
- INIT_LIST_HEAD(&rq->queuelist);
- } else {
- struct blk_mq_alloc_data data = {
- .q = q,
- .nr_tags = 1,
- .cmd_flags = bio->bi_opf,
- };
-
- if (plug) {
- data.nr_tags = plug->nr_ios;
- plug->nr_ios = 1;
- data.cached_rq = &plug->cached_rq;
- }
- rq = __blk_mq_alloc_requests(&data);
- if (unlikely(!rq)) {
- rq_qos_cleanup(q, bio);
- if (bio->bi_opf & REQ_NOWAIT)
- bio_wouldblock_error(bio);
- goto queue_exit;
- }
- }
+ rq = blk_mq_get_request(q, plug, bio);
+ if (unlikely(!rq))
+ goto queue_exit;
trace_block_getrq(bio);
This is in preparation for a fix, but serves as a cleanup as well moving the cached vs regular alloc logic out of blk_mq_submit_bio(). Signed-off-by: Jens Axboe <axboe@kernel.dk> --- block/blk-mq.c | 71 ++++++++++++++++++++++++++++++++++---------------- 1 file changed, 48 insertions(+), 23 deletions(-)