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Diffstat (limited to 'block/blk-mq.c')
-rw-r--r--block/blk-mq.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 902c2eb9a0e7..31df47443699 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1269,6 +1269,7 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
struct request *rq;
unsigned int request_count = 0;
struct blk_plug *plug;
+ struct request *same_queue_rq = NULL;
blk_queue_bounce(q, &bio);
@@ -1278,7 +1279,7 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
}
if (!is_flush_fua && !blk_queue_nomerges(q) &&
- blk_attempt_plug_merge(q, bio, &request_count))
+ blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
return;
rq = blk_mq_map_request(q, bio, &data);
@@ -1309,9 +1310,12 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
* issued. So the plug list will have one request at most
*/
if (plug) {
- if (!list_empty(&plug->mq_list)) {
- old_rq = list_first_entry(&plug->mq_list,
- struct request, queuelist);
+ /*
+ * 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);
@@ -1360,7 +1364,7 @@ static void blk_sq_make_request(struct request_queue *q, struct bio *bio)
}
if (!is_flush_fua && !blk_queue_nomerges(q) &&
- blk_attempt_plug_merge(q, bio, &request_count))
+ blk_attempt_plug_merge(q, bio, &request_count, NULL))
return;
rq = blk_mq_map_request(q, bio, &data);