blk-mq: fix race in IO start accounting
Commit c6d600c6 opened up a small race where we could attempt to
account IO completion on a request, racing with IO start accounting.
Fix this up by ensuring that we've accounted for IO start before
inserting the request.
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9f07a26..526feee 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1088,17 +1088,15 @@
}
if (!(hctx->flags & BLK_MQ_F_SHOULD_MERGE)) {
- init_request_from_bio(rq, bio);
-
+ blk_mq_bio_to_request(rq, bio);
spin_lock(&ctx->lock);
insert_rq:
__blk_mq_insert_request(hctx, rq, false);
spin_unlock(&ctx->lock);
- blk_account_io_start(rq, 1);
} else {
spin_lock(&ctx->lock);
if (!blk_mq_attempt_merge(q, ctx, bio)) {
- init_request_from_bio(rq, bio);
+ blk_mq_bio_to_request(rq, bio);
goto insert_rq;
}