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Subject: Re: remove dead bdi congestion leftovers
To:     Christoph Hellwig <hch@lst.de>
Cc:     Tejun Heo <tj@kernel.org>, dm-devel@redhat.com,
        cgroups@vger.kernel.org, linux-block@vger.kernel.org,
        drbd-dev@lists.linbit.com, linux-bcache@vger.kernel.org,
        linux-raid@vger.kernel.org, linux-btrfs@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20200701090622.3354860-1-hch@lst.de>
 <b5d6df17-68af-d535-79e4-f95e16dd5632@kernel.dk>
 <20200709053233.GA3243@lst.de>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <82e2785d-2091-1986-0014-3b7cea7cd0d8@kernel.dk>
Date:   Thu, 9 Jul 2020 07:58:58 -0600
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On 7/8/20 11:32 PM, Christoph Hellwig wrote:
> On Wed, Jul 08, 2020 at 05:14:29PM -0600, Jens Axboe wrote:
>> On 7/1/20 3:06 AM, Christoph Hellwig wrote:
>>> Hi Jens,
>>>
>>> we have a lot of bdi congestion related code that is left around without
>>> any use.  This series removes it in preparation of sorting out the bdi
>>> lifetime rules properly.
>>
>> Please run series like this through a full compilation, for both this one
>> and the previous series I had to fix up issues like this:
>>
>> drivers/md/bcache/request.c: In function ‘bch_cached_dev_request_init’:
>> drivers/md/bcache/request.c:1233:18: warning: unused variable ‘g’ [-Wunused-variable]
>>  1233 |  struct gendisk *g = dc->disk.disk;
>>       |                  ^
>> drivers/md/bcache/request.c: In function ‘bch_flash_dev_request_init’:
>> drivers/md/bcache/request.c:1320:18: warning: unused variable ‘g’ [-Wunused-variable]
>>  1320 |  struct gendisk *g = d->disk;
>>       |                  ^
>>
>> Did the same here, applied it.
> 
> And just like the previous one I did, and the compiler did not complain.
> There must be something about certain gcc versions not warning about
> variables that are initialized but not otherwise used.

Are you using gcc-10? It sucks for that. gcc-9 seems to reliably hit
these cases for me, not sure why gcc-10 doesn't. And the ones quoted
above are about as trivial as they can get.

-- 
Jens Axboe