2023-05-22 13:21:44

by Yu Kuai

Subject: [PATCH RESEND] blk-wbt: fix that wbt can't be disabled by default

From: Yu Kuai <[email protected]>

commit b11d31ae01e6 ("blk-wbt: remove unnecessary check in
wbt_enable_default()") removes the checking of CONFIG_BLK_WBT_MQ by
mistake, which is used to control enable or disable wbt by default.

Fix the problem by adding back the checking. This patch also do a litter
cleanup to make related code more readable.

Fixes: b11d31ae01e6 ("blk-wbt: remove unnecessary check in wbt_enable_default()")
Reported-by: Lukas Bulwahn <[email protected]>
Link: https://lore.kernel.org/lkml/CAKXUXMzfKq_J9nKHGyr5P5rvUETY4B-fxoQD4sO+NYjFOfVtZA@mail.gmail.com/t/
Signed-off-by: Yu Kuai <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
block/blk-wbt.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index e49a48684532..9ec2a2f1eda3 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -730,14 +730,16 @@ void wbt_enable_default(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
struct rq_qos *rqos;
- bool disable_flag = q->elevator &&
- test_bit(ELEVATOR_FLAG_DISABLE_WBT, &q->elevator->flags);
+ bool enable = IS_ENABLED(CONFIG_BLK_WBT_MQ);
+
+ if (q->elevator &&
+ test_bit(ELEVATOR_FLAG_DISABLE_WBT, &q->elevator->flags))
+ enable = false;

/* Throttling already enabled? */
rqos = wbt_rq_qos(q);
if (rqos) {
- if (!disable_flag &&
- RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT)
+ if (enable && RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT)
RQWB(rqos)->enable_state = WBT_STATE_ON_DEFAULT;
return;
}
@@ -746,7 +748,7 @@ void wbt_enable_default(struct gendisk *disk)
if (!blk_queue_registered(q))
return;

- if (queue_is_mq(q) && !disable_flag)
+ if (queue_is_mq(q) && enable)
wbt_init(disk);
}
EXPORT_SYMBOL_GPL(wbt_enable_default);
--
2.39.2

2023-05-23 06:28:34

by Christoph Hellwig

Subject: Re: [PATCH RESEND] blk-wbt: fix that wbt can't be disabled by default

Looks good:

Reviewed-by: Christoph Hellwig <[email protected]>

2023-05-23 17:22:08

by Jens Axboe

Subject: Re: [PATCH RESEND] blk-wbt: fix that wbt can't be disabled by default

On Mon, 22 May 2023 20:18:54 +0800, Yu Kuai wrote:
> commit b11d31ae01e6 ("blk-wbt: remove unnecessary check in
> wbt_enable_default()") removes the checking of CONFIG_BLK_WBT_MQ by
> mistake, which is used to control enable or disable wbt by default.
>
> Fix the problem by adding back the checking. This patch also do a litter
> cleanup to make related code more readable.
>
> [...]

Applied, thanks!

[1/1] blk-wbt: fix that wbt can't be disabled by default
(no commit info)

Best regards,
--
Jens Axboe