2020-04-29 02:08:36

by Zou Wei

Subject: [PATCH -next] blk-mq: Use BUG_ON() instead of BUG()

Fixes coccicheck warning:

block/blk-mq.c:546:2-5: WARNING: Use BUG_ON instead of if condition followed by BUG.

Fixes: 63151a449eba ("blk-mq: allow drivers to hook into I/O completion")
Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Zou Wei <[email protected]>
---
block/blk-mq.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index bcc3a23..49a227e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -542,8 +542,7 @@ EXPORT_SYMBOL(__blk_mq_end_request);

void blk_mq_end_request(struct request *rq, blk_status_t error)
{
- if (blk_update_request(rq, error, blk_rq_bytes(rq)))
- BUG();
+ BUG_ON(blk_update_request(rq, error, blk_rq_bytes(rq)));
__blk_mq_end_request(rq, error);
}
EXPORT_SYMBOL(blk_mq_end_request);
--
2.6.2

2020-04-29 07:28:25

by Christoph Hellwig

Subject: Re: [PATCH -next] blk-mq: Use BUG_ON() instead of BUG()

On Wed, Apr 29, 2020 at 10:10:24AM +0800, Zou Wei wrote:
> Fixes coccicheck warning:
>
> block/blk-mq.c:546:2-5: WARNING: Use BUG_ON instead of if condition followed by BUG.
>
> Fixes: 63151a449eba ("blk-mq: allow drivers to hook into I/O completion")
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: Zou Wei <[email protected]>
> ---
> block/blk-mq.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index bcc3a23..49a227e 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -542,8 +542,7 @@ EXPORT_SYMBOL(__blk_mq_end_request);
>
> void blk_mq_end_request(struct request *rq, blk_status_t error)
> {
> - if (blk_update_request(rq, error, blk_rq_bytes(rq)))
> - BUG();
> + BUG_ON(blk_update_request(rq, error, blk_rq_bytes(rq)));

I don't think hiding something that actually does do the work in a
BUG_ON ever is a good style.

2020-04-29 15:17:37

by Jens Axboe

Subject: Re: [PATCH -next] blk-mq: Use BUG_ON() instead of BUG()

On 4/29/20 1:26 AM, Christoph Hellwig wrote:
> On Wed, Apr 29, 2020 at 10:10:24AM +0800, Zou Wei wrote:
>> Fixes coccicheck warning:
>>
>> block/blk-mq.c:546:2-5: WARNING: Use BUG_ON instead of if condition followed by BUG.
>>
>> Fixes: 63151a449eba ("blk-mq: allow drivers to hook into I/O completion")
>> Reported-by: Hulk Robot <[email protected]>
>> Signed-off-by: Zou Wei <[email protected]>
>> ---
>> block/blk-mq.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>> index bcc3a23..49a227e 100644
>> --- a/block/blk-mq.c
>> +++ b/block/blk-mq.c
>> @@ -542,8 +542,7 @@ EXPORT_SYMBOL(__blk_mq_end_request);
>>
>> void blk_mq_end_request(struct request *rq, blk_status_t error)
>> {
>> - if (blk_update_request(rq, error, blk_rq_bytes(rq)))
>> - BUG();
>> + BUG_ON(blk_update_request(rq, error, blk_rq_bytes(rq)));
>
> I don't think hiding something that actually does do the work in a
> BUG_ON ever is a good style.

Agree, it's a lot less readable. And, not that we've ever done that, but
also fragile in a lot of code bases where a non-debug build would turn
off the BUG_ON() equivalent, and hence never call blk_update_request().
So not a good practice anywhere for statements that have side effects.

--
Jens Axboe