blk-mq: avoid infinite recursion with the FUA flag (a57a178a) · Commits · 戴 / test

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 −0

Original line number	Diff line number	Diff line
		@@ -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;

block/blk-mq.c

+3 −8

Original line number	Diff line number	Diff line
		@@ -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);
		}

		if (run_queue)
		blk_mq_run_hw_queue(hctx, async);

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