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blk-mq: improve blk_mq_try_issue_directly 

Rename blk_mq_try_issue_directly to __blk_mq_try_issue_directly and add a
new wrapper that takes care of RCU / SRCU locking to avoid having
boileplate code in the caller which would get duplicated with new callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig 2017-03-22 15:01:51 -04:00 committed by Jens Axboe
parent 254d259da0
commit 5eb6126e1c
1 changed files with 18 additions and 14 deletions
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32
block/blk-mq.c
View File

@ -1430,7 +1430,7 @@ static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq)
return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true);
}
static void blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie,
static void __blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie,
bool may_sleep)
{
struct request_queue *q = rq->q;
@ -1475,13 +1475,27 @@ insert:
blk_mq_sched_insert_request(rq, false, true, false, may_sleep);
}
static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
struct request *rq, blk_qc_t *cookie)
{
if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
rcu_read_lock();
__blk_mq_try_issue_directly(rq, cookie, false);
rcu_read_unlock();
} else {
unsigned int srcu_idx = srcu_read_lock(&hctx->queue_rq_srcu);
__blk_mq_try_issue_directly(rq, cookie, true);
srcu_read_unlock(&hctx->queue_rq_srcu, srcu_idx);
}
}
static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
{
const int is_sync = op_is_sync(bio->bi_opf);
const int is_flush_fua = op_is_flush(bio->bi_opf);
struct blk_mq_alloc_data data = { .flags = 0 };
struct request *rq;
unsigned int request_count = 0, srcu_idx;
unsigned int request_count = 0;
struct blk_plug *plug;
struct request *same_queue_rq = NULL;
blk_qc_t cookie;
@ -1579,18 +1593,8 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
} else /* is_sync */
old_rq = rq;
blk_mq_put_ctx(data.ctx);
if (!old_rq)
goto done;
if (!(data.hctx->flags & BLK_MQ_F_BLOCKING)) {
rcu_read_lock();
blk_mq_try_issue_directly(old_rq, &cookie, false);
rcu_read_unlock();
} else {
srcu_idx = srcu_read_lock(&data.hctx->queue_rq_srcu);
blk_mq_try_issue_directly(old_rq, &cookie, true);
srcu_read_unlock(&data.hctx->queue_rq_srcu, srcu_idx);
}
if (old_rq)
blk_mq_try_issue_directly(data.hctx, old_rq, &cookie);
goto done;
}