From: Joel Becker <joel.becker@oracle.com>
Date: Tue, 16 Dec 2008 01:13:48 +0000 (-0800)
Subject: ocfs2: Don't hand-code xor in ocfs2_hamming_encode().
X-Git-Tag: v2.6.29-rc1~505^2~16
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e798b3f8a920c82a8e556dd54df97f0d3d0f9144;p=pandora-kernel.git

ocfs2: Don't hand-code xor in ocfs2_hamming_encode().

When I wrote ocfs2_hamming_encode(), I was following documentation of
the algorithm and didn't have quite the (possibly still imperfect) grasp
of it I do now.  As part of this, I literally hand-coded xor.  I would
test a bit, and then add that bit via xor to the parity word.

I can, of course, just do a single xor of the parity word and the source
word (the code buffer bit offset).  This cuts CPU usage by 53% on a
mostly populated buffer (an inode containing utmp.h inline).

Joel

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
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