Re: [PATCH v1] block/mq-deadline: hold elevator_lock in debugfs next_rq show
Bart Van Assche <[email protected]>
| Newsgroups | org.kernel.vger.linux-block,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 7/20/26 11:30 PM, Xixin Liu wrote:
> diff --git a/block/mq-deadline.c b/block/mq-deadline.c
> index 824bfc17b2c6..e7c4a91b2d08 100644
> --- a/block/mq-deadline.c
> +++ b/block/mq-deadline.c
> @@ -842,14 +842,22 @@ static int deadline_##name##_next_rq_show(void *data, \
> struct seq_file *m) \
> { \
> struct request_queue *q = data; \
> - struct deadline_data *dd = q->elevator->elevator_data; \
> - struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
> + struct elevator_queue *e; \
> + struct deadline_data *dd; \
> + struct dd_per_prio *per_prio; \
> struct request *rq; \
> + int ret; \
> \
> + ret = mutex_lock_interruptible(&q->elevator_lock); \
> + if (ret) \
> + return ret; \
> + e = q->elevator; \
> + if (!e) \
> + goto unlock; \
> + dd = e->elevator_data; \
> + per_prio = &dd->per_prio[prio]; \
> rq = deadline_from_pos(per_prio, data_dir, \
> per_prio->latest_pos[data_dir]); \
> if (rq) \
> __blk_mq_debugfs_rq_show(m, rq); \
> +unlock: \
> + mutex_unlock(&q->elevator_lock); \
> return 0; \
> }
>
The above patch uses the wrong lock and brings way too much code under
the lock. Please help with testing this patch:
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 6e8f87e07eb9..c52601c1fa13 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -850,6 +850,7 @@ static int deadline_##name##_next_rq_show(void
*data, \
struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
struct request *rq; \
\
+ guard(spinlock)(&dd->lock); \
rq = deadline_from_pos(per_prio, data_dir, \
per_prio->latest_pos[data_dir]); \
if (rq) \