From: Simon Guinot <sguinot@lacie.com>
Date: Fri, 17 Sep 2010 21:33:51 +0000 (+0200)
Subject: dmaengine: fix interrupt clearing for mv_xor
X-Git-Tag: v2.6.27.55~12
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1aa14af44cc76d3e38ed4a0b321cab7323a59452;p=pandora-kernel.git

dmaengine: fix interrupt clearing for mv_xor

commit cc60f8878eab892c03d06b10f389232b9b66bd83 upstream.

When using simultaneously the two DMA channels on a same engine, some
transfers are never completed. For example, an endless lock can occur
while writing heavily on a RAID5 array (with async-tx offload support
enabled).

Note that this issue can also be reproduced by using the DMA test
client.

On a same engine, the interrupt cause register is shared between two
DMA channels. This patch make sure that the cause bit is only cleared
for the requested channel.

Signed-off-by: Simon Guinot <sguinot@lacie.com>
Tested-by: Luc Saillard <luc@saillard.org>
Acked-by: saeed bishara <saeed.bishara@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

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