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Subject: Re: kmemleak report after 9082e87bfbf8 ("block: remove struct
 bio_batch")
To: Catalin Marinas <catalin.marinas@arm.com>,
        Shaun Tancheff <shaun.tancheff@seagate.com>
References: <20160606112620.GA29910@e104818-lin.cambridge.arm.com>
 <20160606141334.GA6579@lst.de>
 <20160606161245.GC29910@e104818-lin.cambridge.arm.com>
 <CAJVOszD16vfES8e6NcanBJ7P4HHmp635Ln7VVVyraaPnm0jriA@mail.gmail.com>
 <20160607093937.GA7122@localhost>
Cc: Christoph Hellwig <hch@lst.de>, linux-block@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>, Jens Axboe <axboe@fb.com>,
        bart.vanassche@sandisk.com, drysdale@google.com
From: Larry Finger <Larry.Finger@lwfinger.net>
Message-ID: <5756D7AD.1000602@lwfinger.net>
Date: Tue, 7 Jun 2016 09:18:21 -0500
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On 06/07/2016 04:39 AM, Catalin Marinas wrote:
> On Mon, Jun 06, 2016 at 12:09:49PM -0500, Shaun Tancheff wrote:
>> I'm pretty sure it is missing a bio_put() after submit_bio_wait().
>>
>> Please excuse the hack-y patch but I think you need to do something
>> like this ...
>> (Note tabs eaten by gmail).
>>
>> diff --git a/block/blk-lib.c b/block/blk-lib.c
>> index 23d7f30..9e29dc3 100644
>> --- a/block/blk-lib.c
>> +++ b/block/blk-lib.c
>> @@ -113,6 +113,7 @@ int blkdev_issue_discard(struct block_device
>> *bdev, sector_t sector,
>>                  ret = submit_bio_wait(type, bio);
>>                  if (ret == -EOPNOTSUPP)
>>                          ret = 0;
>> +               bio_put(bio);
>>          }
>>          blk_finish_plug(&plug);
>>
>> @@ -165,8 +166,10 @@ int blkdev_issue_write_same(struct block_device
>> *bdev, sector_t sector,
>>                  }
>>          }
>>
>> -       if (bio)
>> +       if (bio) {
>>                  ret = submit_bio_wait(REQ_WRITE | REQ_WRITE_SAME, bio);
>> +               bio_put(bio);
>> +       }
>>          return ret != -EOPNOTSUPP ? ret : 0;
>>   }
>>   EXPORT_SYMBOL(blkdev_issue_write_same);
>> @@ -206,8 +209,11 @@ static int __blkdev_issue_zeroout(struct
>> block_device *bdev, sector_t sector,
>>                  }
>>          }
>>
>> -       if (bio)
>> -               return submit_bio_wait(WRITE, bio);
>> +       if (bio) {
>> +               ret = submit_bio_wait(WRITE, bio);
>> +               bio_put(bio);
>> +               return ret;
>> +       }
>>          return 0;
>>   }
>
> This patch appears to fix the memory leak on my machine.
>
> Tested-by: Catalin Marinas <catalin.marinas@arm.com>

The patch appears to work here as well.

Tested-by: Larry Finger@lwfinger.net

Thanks,

Larry