blk-mq: avoid infinite recursion with the FUA flag
authorChristoph Hellwig <hch@lst.de>
Tue, 16 Sep 2014 21:44:07 +0000 (14:44 -0700)
committerJens Axboe <axboe@fb.com>
Mon, 22 Sep 2014 17:55:19 +0000 (11:55 -0600)
We should not insert requests into the flush state machine from
blk_mq_insert_request.  All incoming flush requests come through
blk_{m,s}q_make_request and are handled there, while blk_execute_rq_nowait
should only be called for BLOCK_PC requests.  All other callers
deal with requests that already went through the flush statemchine
and shouldn't be reinserted into it.

Reported-by: Robert Elliott <Elliott@hp.com>
Debugged-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
block/blk-exec.c
block/blk-mq.c

index f4d27b12c90b2778182cc3c0cf5a6cd09e2b0310..9924725fa50dcac5563d2654a24df0d85cfada7a 100644 (file)
@@ -56,6 +56,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
        bool is_pm_resume;
 
        WARN_ON(irqs_disabled());
+       WARN_ON(rq->cmd_type == REQ_TYPE_FS);
 
        rq->rq_disk = bd_disk;
        rq->end_io = done;
index 1583ed28ea03fae496bb302ebf28a9a985a0765c..a7d70a1bbf3677da45a4be57056f5971a8853a6b 100644 (file)
@@ -963,14 +963,9 @@ void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
 
        hctx = q->mq_ops->map_queue(q, ctx->cpu);
 
-       if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA) &&
-           !(rq->cmd_flags & (REQ_FLUSH_SEQ))) {
-               blk_insert_flush(rq);
-       } else {
-               spin_lock(&ctx->lock);
-               __blk_mq_insert_request(hctx, rq, at_head);
-               spin_unlock(&ctx->lock);
-       }
+       spin_lock(&ctx->lock);
+       __blk_mq_insert_request(hctx, rq, at_head);
+       spin_unlock(&ctx->lock);
 
        if (run_queue)
                blk_mq_run_hw_queue(hctx, async);