On 10/26/2016 05:01 PM, Dave Jones wrote:
On Wed, Oct 26, 2016 at 03:51:01PM -0700, Linus Torvalds wrote:
> Dave: it might be a good idea to split that "WARN_ON_ONCE()" in
> blk_mq_merge_queue_io() into two, since right now it can trigger both
> for the
>
> blk_mq_bio_to_request(rq, bio);
>
> path _and_ for the
>
> if (!blk_mq_attempt_merge(q, ctx, bio)) {
> blk_mq_bio_to_request(rq, bio);
> goto insert_rq;
>
> path. If you split it into two: one before that "insert_rq:" label,
> and one before the "goto insert_rq" thing, then we could see if it is
> just one of the blk_mq_merge_queue_io() cases (or both) that is
> broken..
It's the latter of the two.
[ 12.302392] WARNING: CPU: 3 PID: 272 at block/blk-mq.c:1191
blk_sq_make_request+0x320/0x4d0
I would expect that - so normal request, since we know merging is on. I
just sent out a patch, can you give that a whirl?
Keep Linus' debugging patch, and apply it on top. Below as well, for
reference.
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ddc2eed64771..80a9c45a9235 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1217,9 +1217,7 @@ static struct request *blk_mq_map_request(struct
request_queue *q,
blk_mq_set_alloc_data(&alloc_data, q, 0, ctx, hctx);
rq = __blk_mq_alloc_request(&alloc_data, op, op_flags);
- hctx->queued++;
- data->hctx = hctx;
- data->ctx = ctx;
+ data->hctx->queued++;
return rq;
}
--
Jens Axboe
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