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[Xen-devel] [PATCH] redundant ampersand before array name in __RING_SIZE

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] [PATCH] redundant ampersand before array name in __RING_SIZE macro
From: Richard Miller <9xen@xxxxxxxxxxxx>
Date: Wed, 4 Oct 2006 14:46:46 +0100
Delivery-date: Wed, 04 Oct 2006 06:47:16 -0700
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The __RING_SIZE macro in xen/include/public/io/ring.h has an ampersand
before (_s)->ring which is unnecessary (an array name without subscript already
means "address of"), and causes fussy C compilers like the Plan 9 one to 
generate
very many warning messages like this when the FRONT_RING_INIT macro is used:

        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        warning: etherxen.c:215 address of array/func ignored
        ... etc

Would you like to tidy it up with the attached patch?

-- Richard Miller
# HG changeset patch
# User miller@vt310
# Node ID 16863ad2efc0f6b4abe7b8239f55946aa3f336fc
# Parent  473689acffdbc8b615fbc38ce8a877a904b702ed
Remove redundant '&' before array name in __RING_SIZE macro.

Signed-off-by: Richard Miller <9xen@xxxxxxxxxxxx>

diff -r 473689acffdb -r 16863ad2efc0 xen/include/public/io/ring.h
--- a/xen/include/public/io/ring.h      Tue Oct 03 17:53:42 2006 +0100
+++ b/xen/include/public/io/ring.h      Wed Oct 04 12:27:45 2006 +0100
@@ -25,7 +25,7 @@ typedef unsigned int RING_IDX;
  * power of two (so we can mask with (size-1) to loop around).
  */
 #define __RING_SIZE(_s, _sz) \
-    (__RD32(((_sz) - (long)&(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
+    (__RD32(((_sz) - (long)(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
 
 /*
  * Macros to make the correct C datatypes for a new kind of ring.
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