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From: Michal Hocko <mhocko@kernel.org>
To: Nick Desaulniers <nick.desaulniers@gmail.com>
Cc: akpm@linux-foundation.org, hannes@cmpxchg.org,
	mgorman@techsingularity.net, vbabka@suse.cz, minchan@kernel.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/vmscan: fix unsequenced modification and access warning
Date: Wed, 10 May 2017 11:25:05 +0200	[thread overview]
Message-ID: <20170510092505.GH31466@dhcp22.suse.cz> (raw)
In-Reply-To: <20170510084602.qchu4psnughxrmsz@lostoracle.net>

On Wed 10-05-17 01:46:03, Nick Desaulniers wrote:
> > You can add
> 
> Something that's not clear to me when advised to add, should I be
> uploading a v3 with your acked by? I think I got that wrong the last
> time I asked (which was my first patch to Linux).

If there are no further changes to the patch/changelog then it is not
necessary. The maintainer usually just grabs ackes and reviewed-bys
from the list.

> > But I still do not understand which part of the code is undefined and
> > why.
> 
> It's not immediately clear to me either, but it's super later here...

I would really like to understand that...
 
> >  is this a bug in -Wunsequenced in Clang
> 
> Possibly, I think I already found one earlier tonight.
> 
> https://bugs.llvm.org/show_bug.cgi?id=32985

this seems unrelated. I would try to report this and clarify in the llvm
bugzilla.

> Tomorrow, I'll try to cut down a test case to see if this is indeed a
> compiler bug.  Would you like me to change the commit message to call
> this just a simple clean up, in the meantime?

I would go with the following wording.
"
Clang and its -Wunsequenced emits a warning
(PUT THE FULL WARNING HERE).

While it is not clear to me whether the initialization code violates the
specification (6.7.8 par 19 (ISO/IEC 9899) looks it disagrees) the code
is quite confusing and worth cleaning up anyway. Fix this by reusing
sc.gfp_mask rather than the updated input gfp_mask parameter.
"
-- 
Michal Hocko
SUSE Labs

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  reply	other threads:[~2017-05-10  9:25 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-10  6:53 [PATCH] mm/vmscan: fix unsequenced modification and access warning Nick Desaulniers
2017-05-10  7:15 ` Michal Hocko
2017-05-10  8:27   ` [Patch v2] " Nick Desaulniers
2017-05-10  8:38     ` Michal Hocko
2017-05-16  8:27       ` Michal Hocko
2017-05-17  3:01         ` Nick Desaulniers
2017-05-26  4:43         ` Nick Desaulniers
2017-05-31 15:21           ` Michal Hocko
2017-05-10  8:46   ` [PATCH] " Nick Desaulniers
2017-05-10  9:25     ` Michal Hocko [this message]
2017-05-10 15:40       ` [Patch v3] " Nick Desaulniers
2018-03-21 21:37   ` [PATCH] " Nick Desaulniers
2018-03-22  9:50     ` Michal Hocko

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