From a57a178a490345c7236b0077b3de005754389ed6 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 16 Sep 2014 14:44:07 -0700
Subject: [PATCH] blk-mq: avoid infinite recursion with the FUA flag
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 | 1 +
block/blk-mq.c | 11 +++--------
2 files changed, 4 insertions(+), 8 deletions(-)
diff --git a/block/blk-exec.c b/block/blk-exec.c
index f4d27b12c90b2..9924725fa50dc 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -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;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 1583ed28ea03f..a7d70a1bbf367 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -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);
--
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