Re: [PATCH] block: don't call should_fail_request() for !CONFIG_FAIL_MAKE_REQUEST

Jens Axboe
2021-10-05T17:10:46Z

On 10/5/21 11:04 AM, Bart Van Assche wrote:
> On 10/5/21 8:32 AM, Jens Axboe wrote:
>> Unnecessary function call, if we don't have that specific configuration
>> option enabled.
>>
>> Signed-off-by: Jens Axboe <axboe@kernel.dk>
>>
>> ---
>>
>> diff --git a/block/blk-core.c b/block/blk-core.c
>> index 5454db2fa263..a267f11f55cb 100644
>> --- a/block/blk-core.c
>> +++ b/block/blk-core.c
>> @@ -697,8 +697,10 @@ static inline bool bio_check_ro(struct bio *bio)
>>
>> static noinline int should_fail_bio(struct bio *bio)
>> {
>> +#ifdef CONFIG_FAIL_MAKE_REQUEST
>> if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size))
>> return -EIO;
>> +#endif
>> return 0;
>> }
>> ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);
>
> Has the performance impact of this patch been measured? I'm asking because I
> found the following in blk-core.c:
>
> #ifdef CONFIG_FAIL_MAKE_REQUEST
> [ ... ]
> #else /* CONFIG_FAIL_MAKE_REQUEST */
> static inline bool should_fail_request(struct block_device *part,
> unsigned int bytes)
> {
> return false;
> }
> #endif /* CONFIG_FAIL_MAKE_REQUEST */

True, might be a leftover from some other experimentation. Looks like we
can just ignore that patch.

--
Jens Axboe