From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Sun, 13 Apr 2008 11:48:43 +0000 (-0300)
Subject: V4L/DVB (7580): Fix concurrent read from /proc/videocodecs
X-Git-Tag: v2.6.26-rc1~1084^2~136
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9faa2d75822e1950b3aacc8ccbdf0cdb595e47de;p=pandora-kernel.git

V4L/DVB (7580): Fix concurrent read from /proc/videocodecs

Observation one: ->write_proc and ->data assignments aren't needed. Removed.
Observation two: codecs lists are unprotected. Patch doesn't fix this.
Observation three:
	/proc/videocodecs printout is done to temporary _global_ buffer which
	is freed in between. Consequently, two users hitting this file can
	screwup each other.

Steps to reproduce:

	modprobe videocodec
	while true; do cat /proc/videocodecs &>/dev/null; done &
	while true; do cat /proc/videocodecs &>/dev/null; done &

The fix is switching to seq_files, this removes code, especially some
line-length "logic".

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
---

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