提交 caf8eb0d 编写于 作者: M Ming Lei 提交者: Jens Axboe

blk-mq-sched: move actual dispatching into one helper

So that it becomes easy to support to dispatch from sw queue in the
following patch.

No functional change.
Reviewed-by: NBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: NOmar Sandoval <osandov@fb.com>
Suggested-by: Christoph Hellwig <hch@lst.de> # for simplifying dispatch logic
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
上级 5e3d02bb
......@@ -89,12 +89,26 @@ static bool blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx)
return false;
}
static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
{
struct request_queue *q = hctx->queue;
struct elevator_queue *e = q->elevator;
LIST_HEAD(rq_list);
do {
struct request *rq = e->type->ops.mq.dispatch_request(hctx);
if (!rq)
break;
list_add(&rq->queuelist, &rq_list);
} while (blk_mq_dispatch_rq_list(q, &rq_list));
}
void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
{
struct request_queue *q = hctx->queue;
struct elevator_queue *e = q->elevator;
const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request;
bool do_sched_dispatch = true;
LIST_HEAD(rq_list);
/* RCU or SRCU read lock is needed before checking quiesced flag */
......@@ -122,30 +136,21 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
* scheduler, we can no longer merge or sort them. So it's best to
* leave them there for as long as we can. Mark the hw queue as
* needing a restart in that case.
*
* We want to dispatch from the scheduler if there was nothing
* on the dispatch list or we were able to dispatch from the
* dispatch list.
*/
if (!list_empty(&rq_list)) {
blk_mq_sched_mark_restart_hctx(hctx);
do_sched_dispatch = blk_mq_dispatch_rq_list(q, &rq_list);
} else if (!has_sched_dispatch) {
if (blk_mq_dispatch_rq_list(q, &rq_list) && has_sched_dispatch)
blk_mq_do_dispatch_sched(hctx);
} else if (has_sched_dispatch) {
blk_mq_do_dispatch_sched(hctx);
} else {
blk_mq_flush_busy_ctxs(hctx, &rq_list);
blk_mq_dispatch_rq_list(q, &rq_list);
}
/*
* We want to dispatch from the scheduler if there was nothing
* on the dispatch list or we were able to dispatch from the
* dispatch list.
*/
if (do_sched_dispatch && has_sched_dispatch) {
do {
struct request *rq;
rq = e->type->ops.mq.dispatch_request(hctx);
if (!rq)
break;
list_add(&rq->queuelist, &rq_list);
} while (blk_mq_dispatch_rq_list(q, &rq_list));
}
}
bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
......
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