From: Ed L. Cashin <ecashin@coraid.com>
Date: Tue, 20 Sep 2005 02:57:36 +0000 (-0700)
Subject: [BYTEORDER]: Document alignment and byteorder macros
X-Git-Tag: v3.12-rc1~41436^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e0487992ce1dd7ae7da9c6aabdb19570bb95432b;p=kernel%2Fkernel-generic.git

[BYTEORDER]: Document alignment and byteorder macros

This patch comments the fact that although passing le64_to_cpup et
al. is within the intended use of the byteorder macros, using
get_unaligned is the recommended way to go.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/include/linux/byteorder/generic.h b/include/linux/byteorder/generic.h
index 5fde6f4..04bd756 100644
--- a/include/linux/byteorder/generic.h
+++ b/include/linux/byteorder/generic.h
@@ -5,6 +5,10 @@
  * linux/byteorder_generic.h
  * Generic Byte-reordering support
  *
+ * The "... p" macros, like le64_to_cpup, can be used with pointers
+ * to unaligned data, but there will be a performance penalty on 
+ * some architectures.  Use get_unaligned for unaligned data.
+ *
  * Francois-Rene Rideau <fare@tunes.org> 19970707
  *    gathered all the good ideas from all asm-foo/byteorder.h into one file,
  *    cleaned them up.