From: Manfred Spraul <manfred@colorfullife.com>
To: Davidlohr Bueso <davidlohr@hp.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
1vier1@web.de
Subject: Re: [PATCH 2/6] ipc/sem.c: Bugfix for semctl(,,GETZCNT)
Date: Tue, 13 May 2014 19:43:50 +0200 [thread overview]
Message-ID: <537259D6.6020407@colorfullife.com> (raw)
In-Reply-To: <1399918300.2648.24.camel@buesod1.americas.hpqcorp.net>
Hi Davidlohr,
On 05/12/2014 08:11 PM, Davidlohr Bueso wrote:
> On Sat, 2014-05-10 at 12:03 +0200, Manfred Spraul wrote:
>> GETZCNT is supposed to return the number of threads that wait until
>> a semaphore value becomes 0.
>> The current implementation overlooks complex operations that contain
>> both wait-for-zero operation and operations that alter at least one semaphore.
> Indeed. the pending_alter list does represent blocked processes on the
> sem. Good catch. Btw, how on earth did you run into this? reading the
> code or a real case?
Reading the code.
Or more accurately:
Rewriting it, i.e. I first starting coding the new semncnt/semzcnt code,
then I noticed that the current code is buggy.
>> The patch fixes that.
>> It's intentionally copy&paste, this will be cleaned up in the next patch.
> Instead I would have expected this patch to actually come after the
> count_* refactoring.
>
In this case:
First the bugfix, as simple as possible, then the new features.
--
Manfred
next prev parent reply other threads:[~2014-05-13 17:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-10 10:03 [PATCH 0/6] ipc/sem.c: Fix semctl(,,{GETNCNT,GETZCNT}) Manfred Spraul
2014-05-10 10:03 ` [PATCH 1/6] ipc/sem.c: further whitespace cleanups Manfred Spraul
2014-05-10 10:03 ` [PATCH 2/6] ipc/sem.c: Bugfix for semctl(,,GETZCNT) Manfred Spraul
2014-05-10 10:03 ` [PATCH 3/6] ipc/sem.c: remove code duplication Manfred Spraul
2014-05-10 10:03 ` [PATCH 4/6] ipc/sem.c: Change perform_atomic_semop parameters Manfred Spraul
2014-05-10 10:03 ` [PATCH 5/6] ipc/sem.c: Store which operation blocks in perform_atomic_semop() Manfred Spraul
2014-05-10 10:03 ` [PATCH 6/6] ipc/sem.c: make semctl(,,{GETNCNT,GETZCNT}) standard compliant Manfred Spraul
2014-05-14 14:52 ` Davidlohr Bueso
2014-05-14 22:30 ` Andrew Morton
2014-05-15 4:24 ` Manfred Spraul
2014-05-13 0:04 ` [PATCH 4/6] ipc/sem.c: Change perform_atomic_semop parameters Davidlohr Bueso
2014-05-12 18:19 ` [PATCH 3/6] ipc/sem.c: remove code duplication Davidlohr Bueso
2014-05-12 18:11 ` [PATCH 2/6] ipc/sem.c: Bugfix for semctl(,,GETZCNT) Davidlohr Bueso
2014-05-13 17:43 ` Manfred Spraul [this message]
2014-05-11 23:34 ` [PATCH 1/6] ipc/sem.c: further whitespace cleanups Davidlohr Bueso
2014-05-12 17:50 ` Manfred Spraul
2014-05-12 2:56 ` [PATCH 0/6] ipc/sem.c: Fix semctl(,,{GETNCNT,GETZCNT}) Davidlohr Bueso
2014-05-12 8:02 ` Michael Kerrisk (man-pages)
2014-05-12 17:43 ` Manfred Spraul
-- strict thread matches above, loose matches on Subject: below --
2014-05-18 7:58 Manfred Spraul
2014-05-18 7:58 ` [PATCH 1/6] ipc/sem.c: further whitespace cleanups Manfred Spraul
2014-05-18 7:58 ` [PATCH 2/6] ipc/sem.c: Bugfix for semctl(,,GETZCNT) Manfred Spraul
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