From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH] ipc/sem: 64bit union semun definition Date: Tue, 05 May 2015 23:40:17 +0200 Message-ID: <3111248.ei0HoJaVIp@wuerfel> References: <1430850523-7522-1-git-send-email-a22017@motorola.com> <2165666.hrkl3t0kHm@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sandy Sun Cc: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On Tuesday 05 May 2015 14:09:14 Sandy Sun wrote: > Hi Arnd, > > If user space uses union semun to define.It will use semid_ds not > semid64_ds. > > I used LTP test case semctl01 IPC_STAT to do the test on 64 bit > system.According to the test results: > > Before the change, semun uses semid_ds, the field of sem_nsems reporting of > semaphore STAT info is incorrect: > > semctl01 1 TFAIL : semaphore STAT info is incorrect > semctl01 2 TFAIL : semaphore mode info is incorrect > > After this change, the return value is correct: > semctl01 1 TPASS : buf.sem_nsems and buf.sem_perm.mode are correct > semctl01 2 TPASS : buf.sem_perm.mode is correct I don't understand: semctl01 does not reference 'union semun64'. How does this change make a difference, and why would that difference be limited to 64-bit systems? Arnd