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 <[email protected]> Debugged-by: Ming Lei <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
xlks · Sep 22, 2014 · a57a178 · a57a178
1 parent 683d0e1
commit a57a178
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Showing 2 changed files with 4 additions and 8 deletions.
diff --git 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
@@ -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);