From: Bob Copeland <me@bobcopeland.com>
Date: Thu, 8 Apr 2010 03:55:58 +0000 (-0400)
Subject: ath5k: fix race condition in tx desc processing
X-Git-Tag: v2.6.35-rc1~473^2~460^2^2~32
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a05988bbbef5ac2391fe696646f0b80708f33f2e;p=pandora-kernel.git

ath5k: fix race condition in tx desc processing

As pointed out by Benoit Papillault, there is a potential
race condition between the host and the hardware in reading
the next link in the transmit descriptor list:

cpu0              hw
                  tx for buf completed
                  raise tx_ok interrupt
process buf
buf->ds_link = 0
                  read buf->ds_link

This change checks txdp before processing a descriptor
(if there are any subsequent descriptors) to see if
hardware moved on.  We'll then process this descriptor on
the next tasklet.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
---

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