On 5/28/20 8:34 AM, Keith Busch wrote:
> For when drivers have a need to bypass error injection.
>
> Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
> ---
> v2->v3: Use _GPL export
>
> block/blk-mq.c | 3 ++-
> include/linux/blk-mq.h | 1 +
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index cac11945f602..e62559ac7c45 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -556,7 +556,7 @@ static void __blk_mq_complete_request_remote(void *data)
> q->mq_ops->complete(rq);
> }
>
> -static void __blk_mq_complete_request(struct request *rq)
> +void __blk_mq_complete_request(struct request *rq)
> {
> struct blk_mq_ctx *ctx = rq->mq_ctx;
> struct request_queue *q = rq->q;
> @@ -602,6 +602,7 @@ static void __blk_mq_complete_request(struct request *rq)
> }
> put_cpu();
> }
> +EXPORT_SYMBOL_GPL(__blk_mq_complete_request);
>
> static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)
> __releases(hctx->srcu)
> diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
> index d7307795439a..cfe7eac3764e 100644
> --- a/include/linux/blk-mq.h
> +++ b/include/linux/blk-mq.h
> @@ -494,6 +494,7 @@ void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list);
> void blk_mq_kick_requeue_list(struct request_queue *q);
> void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs);
> bool blk_mq_complete_request(struct request *rq);
> +void __blk_mq_complete_request(struct request *rq);
> bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list,
> struct bio *bio, unsigned int nr_segs);
> bool blk_mq_queue_stopped(struct request_queue *q);
The null block driver requires this as well.
Otherwise, the below would hang forever because timeout handler keeps failing.
# echo 100 > /sys/kernel/debug/fail_io_timeout/probability
# echo 1000 > /sys/kernel/debug/fail_io_timeout/times
# echo 1 > /sys/block/nullb0/io-timeout-fail
# dd if=/dev/zero of=/dev/nullb0 bs=512 count=1 oflag=direct
With below patch, the timeout handler is able to complete the IO.
diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index ce9e33603a4d..ba107b264fab 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1397,7 +1397,7 @@ static bool should_requeue_request(struct request *rq)
static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
{
pr_info("rq %p timed out\n", rq);
- blk_mq_complete_request(rq);
+ __blk_mq_complete_request(rq);
return BLK_EH_DONE;
}
I would wait for the new exported API name until I send out the above.
Perhaps there are more drivers that require such kind of change, but in more
specific corner case.
Dongli Zhang
