From: Ming Lei <ming.lei@xxxxxxxxxx>
commit a6a252e6491443c1c18eab7e254daee63d4a7a04 upstream
In case of IO scheduler we always pre-allocate one driver tag before
calling blk_insert_flush(), and flush request will be marked as
RQF_FLUSH_SEQ once it is in flush machinery.
So if RQF_FLUSH_SEQ isn't set, we call blk_insert_flush() to handle
the request, otherwise the flush request is dispatched to ->dispatch
list directly.
This is a preparation patch for not preallocating a driver tag for flush
requests, and for not treating flush requests as a special case. This is
similar to what the legacy path does.
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxxx>
---
block/blk-mq-sched.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 13a27d4d1671..e7094f44afaf 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -345,21 +345,23 @@ void blk_mq_sched_request_inserted(struct request *rq)
EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted);
static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx,
+ bool has_sched,
struct request *rq)
{
- if (rq->tag == -1) {
+ /* dispatch flush rq directly */
+ if (rq->rq_flags & RQF_FLUSH_SEQ) {
+ spin_lock(&hctx->lock);
+ list_add(&rq->queuelist, &hctx->dispatch);
+ spin_unlock(&hctx->lock);
+ return true;
+ }
+
+ if (has_sched) {
rq->rq_flags |= RQF_SORTED;
- return false;
+ WARN_ON(rq->tag != -1);
}
- /*
- * If we already have a real request tag, send directly to
- * the dispatch list.
- */
- spin_lock(&hctx->lock);
- list_add(&rq->queuelist, &hctx->dispatch);
- spin_unlock(&hctx->lock);
- return true;
+ return false;
}
/*
@@ -385,12 +387,13 @@ void blk_mq_sched_insert_request(struct request *rq, bool at_head,
struct blk_mq_ctx *ctx = rq->mq_ctx;
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
- if (rq->tag == -1 && op_is_flush(rq->cmd_flags)) {
+ /* flush rq in flush machinery need to be dispatched directly */
+ if (!(rq->rq_flags & RQF_FLUSH_SEQ) && op_is_flush(rq->cmd_flags)) {
blk_mq_sched_insert_flush(hctx, rq, can_block);
return;
}
- if (e && blk_mq_sched_bypass_insert(hctx, rq))
+ if (blk_mq_sched_bypass_insert(hctx, !!e, rq))
goto run;
if (e && e->type->ops.mq.insert_requests) {
@@ -428,7 +431,7 @@ void blk_mq_sched_insert_requests(struct request_queue *q,
list_for_each_entry_safe(rq, next, list, queuelist) {
if (WARN_ON_ONCE(rq->tag != -1)) {
list_del_init(&rq->queuelist);
- blk_mq_sched_bypass_insert(hctx, rq);
+ blk_mq_sched_bypass_insert(hctx, true, rq);
}
}
}
--
2.7.4
