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Date: Wed, 20 Aug 2008 01:37:36 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Ian Campbell <ijc@hellion.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       stable@vger.kernel.org, Jaya Kumar <jayakumar.lkml@gmail.com>,
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       Jeremy Fitzhardinge <jeremy@goop.org>, Kel Modderman <kel@otaku42.de>,
       Markus Armbruster <armbru@redhat.com>
Subject: Re: [PATCH] fbdefio: add set_page_dirty handler to deferred IO FB
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On Wed, 20 Aug 2008 09:13:23 +0100 Ian Campbell <ijc@hellion.org.uk> wrote:

> Perhaps applying the band-aid at open time instead would be preferred?

That would be less racy, I expect.  Implement fb_ops.fb_open() within
drivers/video/fb_defio.c and do the address_space_operations overwrite
there.  Hopefully that will ensure that the address_space_operations
instance is stable before anyone uses it for anything serious.

It'd be better to hook in at inode creation time but afaict that's not
available for the /dev/fb0 node.

<tries to write a patch>

OK, seems that fb_ops.fb_open() has no way of getting at the `struct
file *' which is being opened (wtf?).  Screwed.  Need to change
fb_ops.fb_open(), or add a new fb_ops.fb_open_sane().




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