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From: Jan Harkes <jaharkes@cs.cmu.edu>
To: David Howells <dhowells@redhat.com>
Cc: linux-api@vger.kernel.org, linux-kbuild@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 05/11] UAPI: coda: Don't use internal kernel structs in UAPI
Date: Wed, 5 Sep 2018 12:54:47 -0400	[thread overview]
Message-ID: <20180905165447.gnjcc2xbgaem3ue3@cs.cmu.edu> (raw)
In-Reply-To: <153616291029.23468.16421004714304578585.stgit@warthog.procyon.org.uk>

On Wed, Sep 05, 2018 at 04:55:10PM +0100, David Howells wrote:
> The size and layout of internal kernel structures may not be relied upon
> outside of the kernel and may even change in a containerised environment if
> a container image is frozen and shifted to another machine.
> 
> Excise these from Coda's upc_req struct.

Argh, that won't work.

I still have to look at where this structure is used exactly, but...

Either this structure is used by the messages that the kernel sends to
userspace, in which case we don't want the kernel to pack the larger
structure that includes a list_head and a wait_queue_head_t in the
message while userspace reads as if it was a smaller structure without
those.

But my gut feeling is that this is not part of the upcall request
messages and never gets to userspace and as such shouldn't be in uapi to
begin with.

Jan

  reply	other threads:[~2018-09-05 21:56 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-05 15:54 [RFC] UAPI: Check headers by compiling all together as C++ David Howells
2018-09-05 15:55 ` [PATCH 05/11] UAPI: coda: Don't use internal kernel structs in UAPI David Howells
2018-09-05 16:54   ` Jan Harkes [this message]
2018-09-05 17:12   ` Yann Droneaud
2018-09-05 17:28     ` Jan Harkes
2018-09-05 17:24   ` David Howells
2018-09-06  7:13   ` David Howells
2018-09-06 11:52     ` Yann Droneaud
2018-09-06 12:16       ` Jan Harkes
2018-09-06 14:53     ` David Howells
2018-09-05 15:55 ` [PATCH 07/11] UAPI: nilfs2: Fix use of undefined byteswapping functions David Howells
2018-09-05 22:20   ` Al Viro
2018-09-05 16:55 ` [RFC] UAPI: Check headers by compiling all together as C++ Greg KH
2018-09-05 17:33   ` Yann Droneaud
2018-09-05 17:42     ` Michael S. Tsirkin
2018-09-06  7:12     ` Yann Droneaud
2018-09-05 19:22   ` Jan Engelhardt
2018-09-05 17:50 ` David Howells

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