From: Chen Gang <gang.chen@asianux.com>
To: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
kosaki.motohiro@gmail.com, riel@redhat.com, hughd@google.com,
xemul@parallels.com, liwanp@linux.vnet.ibm.com,
gorcunov@gmail.com, linux-mm@kvack.org,
akpm@linux-foundation.org
Subject: Re: [PATCH v2] mm/shmem.c: check the return value of mpol_to_str()
Date: Tue, 17 Sep 2013 08:45:09 +0800 [thread overview]
Message-ID: <5237A615.5050405@asianux.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1309161309490.26194@chino.kir.corp.google.com>
On 09/17/2013 04:13 AM, David Rientjes wrote:
> On Mon, 16 Sep 2013, Chen Gang wrote:
>
>> Hmm... I am not quite sure: a C compiler is clever enough to know about
>> that.
>>
>> At least, for ANSI C definition, the C compiler has no duty to know
>> about that.
>>
>> And it is not for an optimization, either, so I guess the C compiler has
>> no enought interests to support this features (know about that).
>>
>
> What on earth are we talking about in this thread?
>
??
> Rename mpol_to_str() to __mpol_to_str(). Make a static inline function in
> mempolicy.h named mpol_to_str(). That function does BUILD_BUG_ON(maxlen <
> 64) and then calls __mpol_to_str().
>
> Modify __mpol_to_str() to store "unknown" when mpol->mode does not match
> any known MPOL_* constant.
>
Can we be sure 'maxlen' should not be less than 64? For show_numa_map()
in fs/proc/task_mmu.c, it use 50 which is less than 64, is it correct?
> Both functions can now return void.
>
> This is like a ten line diff. Seriously.
>
>
Can we be sure that our output contents are always less than 64 bytes?
Do we need BUG_ON() instead of all '-ENOSPC' in mpol_to_str()?
Hmm... If assume what you said above was always correct: "we are always
sure 64 bytes is enough, and 'maxlen' should be never less than 64".
It would be better to use a structure (which has a member "char buf[64]") pointer instead of 'buffer' and 'maxlen'.
(and also still need check 64 memory bondary and '\0' within mpol_to_str).
Thanks.
--
Chen Gang
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next prev parent reply other threads:[~2013-09-17 0:46 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-20 3:56 [PATCH 0/3] mm: mempolicy: the failure processing about mpol_to_str() Chen Gang
2013-08-20 3:56 ` Chen Gang
2013-08-20 3:57 ` [PATCH 1/3] mm/mempolicy.c: still fill buffer as full as possible when buffer space is not enough in mpol_to_str() Chen Gang
2013-08-20 3:57 ` Chen Gang
2013-08-20 3:58 ` [PATCH 2/3] fs/proc/task_mmu.c: check the return value of mpol_to_str() Chen Gang
2013-08-20 3:58 ` Chen Gang
2013-08-20 3:59 ` [PATCH 3/3] mm/shmem.c: " Chen Gang
2013-08-20 3:59 ` Chen Gang
2013-08-20 5:30 ` [PATCH 0/3] mm: mempolicy: the failure processing about mpol_to_str() Cyrill Gorcunov
2013-08-20 5:30 ` Cyrill Gorcunov
2013-08-20 5:41 ` Chen Gang
2013-08-20 5:41 ` Chen Gang
2013-08-20 6:47 ` Cyrill Gorcunov
2013-08-20 6:47 ` Cyrill Gorcunov
2013-08-20 7:48 ` Chen Gang
2013-08-20 7:48 ` Chen Gang
2013-08-20 7:51 ` Chen Gang
2013-08-20 7:51 ` Chen Gang
2013-08-20 8:09 ` Chen Gang
2013-08-20 8:09 ` Chen Gang
2013-08-20 8:13 ` Chen Gang F T
2013-08-20 8:13 ` Chen Gang F T
2013-08-20 8:20 ` Chen Gang
2013-08-20 8:20 ` Chen Gang
2013-08-20 8:25 ` Cyrill Gorcunov
2013-08-20 8:25 ` Cyrill Gorcunov
2013-08-20 8:31 ` Chen Gang
2013-08-20 8:31 ` Chen Gang
2013-08-21 2:21 ` [PATCH 0/3] mm: shmem: check the return value of mpol_to_str() Chen Gang
2013-08-21 2:21 ` Chen Gang
2013-08-21 2:22 ` [PATCH 1/3] fs/proc/task_mmu.c: " Chen Gang
2013-08-21 2:22 ` Chen Gang
2013-08-21 2:23 ` [PATCH 2/3] mm/shmem.c: let shmem_show_mpol() return value Chen Gang
2013-08-21 2:23 ` Chen Gang
2013-08-21 2:24 ` [PATCH 3/3] mm/shmem.c: check the return value of mpol_to_str() Chen Gang
2013-08-21 2:24 ` Chen Gang
2013-08-21 22:03 ` [PATCH 2/3] mm/shmem.c: let shmem_show_mpol() return value Andrew Morton
2013-08-21 22:03 ` Andrew Morton
2013-08-22 0:52 ` Chen Gang
2013-08-22 0:52 ` Chen Gang
2013-08-22 1:04 ` [PATCH] mm/shmem.c: check the return value of mpol_to_str() Chen Gang
2013-08-22 1:04 ` Chen Gang
2013-09-03 5:32 ` Chen Gang
2013-09-03 5:32 ` Chen Gang
2013-09-05 0:24 ` [PATCH v2] " Chen Gang
2013-09-09 20:30 ` David Rientjes
2013-09-10 0:47 ` Chen Gang
2013-09-10 6:43 ` David Rientjes
2013-09-10 7:01 ` Chen Gang
2013-09-12 0:33 ` David Rientjes
2013-09-12 2:19 ` KOSAKI Motohiro
2013-09-12 3:13 ` Chen Gang
2013-09-13 21:12 ` David Rientjes
2013-09-14 2:51 ` KOSAKI Motohiro
2013-09-16 3:27 ` Chen Gang
2013-09-16 20:13 ` David Rientjes
2013-09-17 0:45 ` Chen Gang [this message]
2013-09-17 22:51 ` David Rientjes
2013-09-18 1:20 ` Chen Gang
2013-09-12 3:02 ` Chen Gang
2013-09-12 18:19 ` KOSAKI Motohiro
2013-09-13 2:23 ` Chen Gang
2013-09-13 16:50 ` KOSAKI Motohiro
2013-09-16 2:55 ` Chen Gang
2013-09-16 16:16 ` KOSAKI Motohiro
2013-09-17 1:10 ` Chen Gang
2013-09-17 22:53 ` David Rientjes
2013-09-18 1:37 ` Chen Gang
2013-09-18 22:17 ` David Rientjes
2013-09-13 21:14 ` David Rientjes
2013-09-16 3:17 ` Chen Gang
2013-09-25 2:58 ` [patch] mm, mempolicy: make mpol_to_str robust and always succeed David Rientjes
2013-09-25 2:58 ` David Rientjes
2013-09-25 3:11 ` Dave Jones
2013-09-25 3:11 ` Dave Jones
2013-09-25 3:18 ` David Rientjes
2013-09-25 3:18 ` David Rientjes
2013-09-25 3:25 ` Dave Jones
2013-09-25 3:25 ` Dave Jones
2013-09-25 17:58 ` David Rientjes
2013-09-25 17:58 ` David Rientjes
2013-09-25 21:30 ` Andrew Morton
2013-09-25 21:30 ` Andrew Morton
2013-09-25 22:06 ` David Rientjes
2013-09-25 22:06 ` David Rientjes
2013-08-21 5:31 ` [PATCH 0/3] mm: shmem: check the return value of mpol_to_str() Cyrill Gorcunov
2013-08-21 5:31 ` Cyrill Gorcunov
2013-08-21 5:48 ` Chen Gang
2013-08-21 5:48 ` Chen Gang
-- strict thread matches above, loose matches on Subject: below --
2013-09-19 0:31 [PATCH v2] mm/shmem.c: " Chen,Gang( 陈刚)
[not found] <20130919003142.B72EC1840296@intranet.asianux.com>
2013-09-23 21:46 ` David Rientjes
2013-09-24 2:28 ` Chen Gang
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