Re: [PATCH 7/7] bcache: fix a regression of code compiling failure in debug.c

From: Coly Li <colyli@suse.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-bcache@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	linux-block@vger.kernel.org
Subject: Re: [PATCH 7/7] bcache: fix a regression of code compiling failure in debug.c
Date: Mon, 12 Apr 2021 21:13:55 +0800	[thread overview]
Message-ID: <254414c0-8f5d-753e-edb1-e9d3805e7bfb@suse.de> (raw)
In-Reply-To: <caf688de-19f6-925e-3059-966fe0d8ce42@kernel.dk>

On 4/12/21 8:50 PM, Jens Axboe wrote:
> On 4/12/21 3:53 AM, Coly Li wrote:
>> On 4/12/21 5:06 PM, Christoph Hellwig wrote:
>>> On Sun, Apr 11, 2021 at 09:43:16PM +0800, Coly Li wrote:
>>>> The patch "bcache: remove PTR_CACHE" introduces a compiling failure in
>>>> debug.c with following error message,
>>>>   In file included from drivers/md/bcache/bcache.h:182:0,
>>>>                    from drivers/md/bcache/debug.c:9:
>>>>   drivers/md/bcache/debug.c: In function 'bch_btree_verify':
>>>>   drivers/md/bcache/debug.c:53:19: error: 'c' undeclared (first use in
>>>>   this function)
>>>>     bio_set_dev(bio, c->cache->bdev);
>>>>                      ^
>>>> This patch fixes the regression by replacing c->cache->bdev by b->c->
>>>> cache->bdev.
>>>
>>> Why not fold this into the offending patch?
>>>
>>
>> I don't know whether I can do it without authorization or agreement from
>> original author. And I see other maintainers handling similar situation
>> by either re-write whole patch or appending an extra fix.
>>
>> If you have a suggested process, I can try it out next time for similar
>> situation.
> 
> What I generally do is just add a line between the SOB's for cases
> like this, ala:
> 
> commit 70aacfe66136809d7f080f89c492c278298719f4
> Author: Pavel Begunkov <asml.silence@gmail.com>
> Date:   Mon Mar 1 13:02:15 2021 +0000
> 
>     io_uring: kill sqo_dead and sqo submission halting
>     
>     As SQPOLL task doesn't poke into ->sqo_task anymore, there is no need to
>     kill the sqo when the master task exits. Before it was necessary to
>     avoid races accessing sqo_task->files with removing them.
>     
>     Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
>     [axboe: don't forget to enable SQPOLL before exit, if started disabled]
>     Signed-off-by: Jens Axboe <axboe@kernel.dk>
> 

This is a new skill to me. Thanks for the hint, I will use such method
to handle similar situation next time.

Coly Li