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From: "H. Peter Anvin" <hpa@zytor.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	David Daney <ddaney.cavm@gmail.com>,
	Ralf Baechle <ralf@linux-mips.org>,
	"H.J. Lu" <hjl.tools@gmail.com>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	mingo@kernel.org, tglx@linutronix.de
Subject: Re: [PATCH 08/10] Use __kernel_ulong_t in struct msqid64_ds
Date: Fri, 18 May 2012 15:08:34 -0700	[thread overview]
Message-ID: <4FB6C862.5060401@zytor.com> (raw)
In-Reply-To: <201205182158.59616.arnd@arndb.de>

On 05/18/2012 02:58 PM, Arnd Bergmann wrote:
> 
> But why do you think it's wrong the way it is? I see the idea of putting
> padding in varying places depending on the endianess as a failed experiment
> and defining a structure that is always the same as the logical conclusion
> from that, even if it's a bit silly to have any padding in it at all.
> 

The *whole point* is to make the structure the same across modes, to
make the compat layer's job easier.

> Being consistent seems more important here than following the intent
> of whoever came up with the concept of the ipc64 data structures
> and was consequently ignored by most people after him.

So you're saying because some architectures introduced a bug, we should
*CONTINUE* to introduce the same bug??  WTF??

> If we really wanted the data structures to be compatible between 32 and
> 64 bit mode, we'd have to use __u64 here but that would mean having to
> change all bits of user code that already rely on the existing x86
> compatible layout.

x86 is doing it right.  Some bigendian architectures blindly copied what
x86 was doing without thinking.  That's a bug on their part, period.

	-hpa



  reply	other threads:[~2012-05-18 22:08 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-17 22:13 [RFC PATCH 00/10] Use __kernel_[u]long_t for x32 user space compatibility H.J. Lu
2012-05-17 22:13 ` [PATCH 01/10] Use __kernel_long_t in struct timex H.J. Lu
2012-05-17 22:32   ` Linus Torvalds
2012-05-17 22:41     ` H. Peter Anvin
2012-05-17 22:50       ` H. Peter Anvin
2012-05-17 22:50       ` Linus Torvalds
2012-05-17 22:55         ` H. Peter Anvin
2012-05-17 22:58           ` Linus Torvalds
2012-05-17 22:56         ` Linus Torvalds
2012-05-17 22:57           ` H. Peter Anvin
2012-05-17 23:51           ` David Daney
2012-05-17 22:13 ` [PATCH 02/10] Use __kernel_ulong_t in struct shm_info H.J. Lu
2012-05-17 22:13 ` [PATCH 03/10] Use __kernel_[u]long_t in linux/resource.h H.J. Lu
2012-05-17 22:13 ` [PATCH 04/10] Use __kernel_long_t in struct msgbuf H.J. Lu
2012-05-17 22:13 ` [PATCH 05/10] Use __kernel_long_t in struct mq_attr H.J. Lu
2012-05-17 22:13 ` [PATCH 06/10] Use __kernel_ulong_t in x86 struct semid64_ds H.J. Lu
2012-05-17 22:13 ` [PATCH 07/10] Use __kernel_ulong_t in struct shmid64_ds/shminfo64 H.J. Lu
2012-05-17 22:13 ` [PATCH 08/10] Use __kernel_ulong_t in struct msqid64_ds H.J. Lu
2012-05-17 23:51   ` H. Peter Anvin
2012-05-18  0:07     ` Linus Torvalds
2012-05-18  0:14       ` H. Peter Anvin
2012-05-18  0:22         ` Linus Torvalds
2012-05-18  0:27           ` H. Peter Anvin
2012-05-18  0:41           ` Linus Torvalds
2012-05-18 11:44             ` David Howells
2012-05-18 21:31             ` Arnd Bergmann
2012-05-18 21:41               ` H. Peter Anvin
2012-05-18 21:58                 ` Arnd Bergmann
2012-05-18 22:08                   ` H. Peter Anvin [this message]
2012-05-19  7:56                     ` Arnd Bergmann
2012-05-19 14:35                       ` Al Viro
2012-05-18  0:29         ` David Daney
2012-05-18  0:31           ` H. Peter Anvin
2012-05-18  0:45             ` David Daney
2012-05-18  0:37           ` H. Peter Anvin
2012-05-18 15:03             ` Chris Metcalf
2012-05-18  3:21     ` H. Peter Anvin
2012-05-18  3:39       ` H.J. Lu
2012-05-18  3:43         ` H.J. Lu
2012-05-18  3:47           ` H.J. Lu
2012-05-18  3:49         ` Linus Torvalds
2012-05-18  3:55           ` H. Peter Anvin
2012-05-18  3:59             ` H.J. Lu
2012-05-18  4:05               ` Linus Torvalds
2012-05-18  4:13                 ` H.J. Lu
2012-05-18 21:21                   ` Arnd Bergmann
2012-05-19 23:47                     ` H. Peter Anvin
2012-05-20  1:32                       ` H.J. Lu
2012-05-20  2:08                         ` H. Peter Anvin
2012-05-18 11:53             ` David Howells
2012-05-18 12:06               ` H.J. Lu
2012-05-18  3:56           ` H.J. Lu
2012-05-18 21:06             ` H. Peter Anvin
2012-05-17 22:13 ` [PATCH 09/10] Use __kernel_ulong_t in struct ipc64_perm H.J. Lu
2012-05-17 22:13 ` [PATCH 10/10] Use __kernel_[u]long_t in x86-64 struct stat H.J. Lu
2012-05-17 23:07 ` [RFC PATCH 00/10] Use __kernel_[u]long_t for x32 user space compatibility David Daney
2012-05-17 23:11   ` H. Peter Anvin
2012-05-17 23:25     ` David Daney
2012-05-17 23:31       ` H. Peter Anvin
2012-05-18  0:19 ` Mike Frysinger
2012-05-18  0:21   ` H. Peter Anvin
2012-05-18  0:38     ` Mike Frysinger

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