Re: Resend: [PATCH] blkdev: fix blkdev_issue_zeroout return value

Jens Axboe
2010-08-06T11:24:08Z

On 2010-08-06 13:15, Dmitry Monakhov wrote:
> Jens Axboe <axboe@kernel.dk> writes:
>
>> On 2010-08-06 12:42, Dmitry Monakhov wrote:
>>> Hi Jens,
>>> Seems that my first mail was missed somewhere.
>>> I've found couple of trivial issues in blkdev_issue_zeroout()
>>> implementation. Unfortunately I've miss during initial testing phase
>>> because always called it with BARRIER|WAIT flags.
>>
>> BTW, this:
>>
>> @@ -218,15 +222,18 @@ submit:
>> /* One of bios in the batch was completed with error.*/
>> ret = -EIO;
>>
>> - if (ret)
>> + if (ret && ret != -ENOMEM)
>> goto out;
>>
>> if (test_bit(BIO_EOPNOTSUPP, &bb.flags)) {
>> ret = -EOPNOTSUPP;
>> goto out;
>> }
>> - if (nr_sects != 0)
>> + if (nr_sects != 0) {
>> + if (ret == -ENOMEM)
>> + io_schedule();
>> goto submit;
>> + }
>> out:
>> return ret;
>> }
>>
>> is broken. Either the caller sets __GFP_WAIT and then bio_alloc() will
>> not fail, or GFP_ATOMIC is used knowing that the call can fail and
>> return ENOMEM. Don't code in retry logic like this.
> Ok, my fault and in fact i've done in explicitly. I just thought
> that blk-layer is some times an exception from general GFP_ATOMIC rule
> because in some places in blk-layer we stick to GFP_NOFAIL semantics
> regardless to actual gfp flags.
>
> New version attached.

Thanks that looks better, now really added.

--
Jens Axboe