linux-kernel - [PATCH] x86, mc146818rtc.h: use do{}while(0) for empty lock_cmos()/unlock

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Date:	Sun, 18 Dec 2011 01:05:31 +0100 (CET)
From:	Jesper Juhl <jj@...osbits.net>
To:	x86@...nel.org
cc:	linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH] x86, mc146818rtc.h: use do{}while(0) for empty
 lock_cmos()/unlock_cmos()

gcc noticed (when using -Wempty-body) that our use of lock_cmos() and
unlock_cmos() in arch/x86/include/asm/mach_traps.h is potentially
problematic :

  arch/x86/include/asm/mach_traps.h:32:15: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body]
  arch/x86/include/asm/mach_traps.h:40:16: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body]

Let's just use the standard 'do {} while (0)' solution. That shuts up
gcc and also prevents future problems if the macros should end up
being used in a similar situation elsewhere.

Signed-off-by: Jesper Juhl <jj@...osbits.net>
---
 arch/x86/include/asm/mc146818rtc.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/mc146818rtc.h b/arch/x86/include/asm/mc146818rtc.h
index 01fdf56..3bb1b14 100644
--- a/arch/x86/include/asm/mc146818rtc.h
+++ b/arch/x86/include/asm/mc146818rtc.h
@@ -81,8 +81,8 @@ static inline unsigned char current_lock_cmos_reg(void)
 #else
 #define lock_cmos_prefix(reg) do {} while (0)
 #define lock_cmos_suffix(reg) do {} while (0)
-#define lock_cmos(reg)
-#define unlock_cmos()
+#define lock_cmos(reg) do {} while (0)
+#define unlock_cmos() do {} while (0)
 #define do_i_have_lock_cmos() 0
 #define current_lock_cmos_reg() 0
 #endif
-- 
1.7.8

-- 
Jesper Juhl <jj@...osbits.net>       http://www.chaosbits.net/
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