Turn the different ways of merging or issuing I/O into a series of if/else
statements instead of the current maze of gotos. Note that this means we
pin the CPU a little longer for some cases as the CTX put is moved to
common code at the end of the function.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-mq.c | 67 +++++++++++++++++++++++-----------------------------------
1 file changed, 27 insertions(+), 40 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 48748cb799ed..18e449cc832f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1534,16 +1534,17 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
cookie = request_to_qc_t(data.hctx, rq);
+ plug = current->plug;
if (unlikely(is_flush_fua)) {
- if (q->elevator)
- goto elv_insert;
blk_mq_bio_to_request(rq, bio);
- blk_insert_flush(rq);
- goto run_queue;
- }
-
- plug = current->plug;
- if (plug && q->nr_hw_queues == 1) {
+ if (q->elevator) {
+ blk_mq_sched_insert_request(rq, false, true,
+ !is_sync || is_flush_fua, true);
+ } else {
+ blk_insert_flush(rq);
+ blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
+ }
+ } else if (plug && q->nr_hw_queues == 1) {
struct request *last = NULL;
blk_mq_bio_to_request(rq, bio);
@@ -1562,8 +1563,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
else
last = list_entry_rq(plug->mq_list.prev);
- blk_mq_put_ctx(data.ctx);
-
if (request_count >= BLK_MAX_REQUEST_COUNT || (last &&
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
blk_flush_plug_list(plug, false);
@@ -1571,56 +1570,44 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
}
list_add_tail(&rq->queuelist, &plug->mq_list);
- goto done;
- } else if (((plug && !blk_queue_nomerges(q)) || is_sync)) {
- struct request *old_rq = NULL;
-
+ } else if (plug && !blk_queue_nomerges(q)) {
blk_mq_bio_to_request(rq, bio);
/*
* We do limited plugging. If the bio can be merged, do that.
* Otherwise the existing request in the plug list will be
* issued. So the plug list will have one request at most
+ *
+ * The plug list might get flushed before this. If that happens,
+ * the plug list is emptry and same_queue_rq is invalid.
*/
- if (plug) {
- /*
- * The plug list might get flushed before this. If that
- * happens, same_queue_rq is invalid and plug list is
- * empty
- */
- if (same_queue_rq && !list_empty(&plug->mq_list)) {
- old_rq = same_queue_rq;
- list_del_init(&old_rq->queuelist);
- }
- list_add_tail(&rq->queuelist, &plug->mq_list);
- } else /* is_sync */
- old_rq = rq;
- blk_mq_put_ctx(data.ctx);
- if (old_rq)
- blk_mq_try_issue_directly(data.hctx, old_rq, &cookie);
- goto done;
- }
+ if (!list_empty(&plug->mq_list))
+ list_del_init(&same_queue_rq->queuelist);
+ else
+ same_queue_rq = NULL;
- if (q->elevator) {
-elv_insert:
- blk_mq_put_ctx(data.ctx);
+ list_add_tail(&rq->queuelist, &plug->mq_list);
+ if (same_queue_rq)
+ blk_mq_try_issue_directly(data.hctx, same_queue_rq,
+ &cookie);
+ } else if (is_sync) {
+ blk_mq_bio_to_request(rq, bio);
+ blk_mq_try_issue_directly(data.hctx, rq, &cookie);
+ } else if (q->elevator) {
blk_mq_bio_to_request(rq, bio);
blk_mq_sched_insert_request(rq, false, true,
!is_sync || is_flush_fua, true);
- goto done;
- }
- if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
+ } else if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
/*
* For a SYNC request, send it to the hardware immediately. For
* an ASYNC request, just ensure that we run it later on. The
* latter allows for merging opportunities and more efficient
* dispatching.
*/
-run_queue:
blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
}
+
blk_mq_put_ctx(data.ctx);
-done:
return cookie;
}
--
2.11.0
