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From: Alexander Beregalov <a.beregalov@gmail.com>
To: arnd@arndb.de
Cc: linux-kernel@vger.kernel.org, David Miller <davem@davemloft.net>,
       sam@ravnborg.org, dhowells@redhat.com,
       Alexander Beregalov <a.beregalov@gmail.com>
Subject: [PATCH] BUG(): CONFIG_BUG=n version of BUG() should be unreachable()
Date: Wed, 23 Dec 2009 04:17:12 +0300
Message-Id: <1261531032-15225-1-git-send-email-a.beregalov@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1048
Lines: 41

Previouss definition of BUG() as 'do {} while(0)' produced compilation
warnings when BUG() was used in default branch of switch() statement
(control reaches end of non-void function).

Example:
unsigned long function()
{
	switch() {
	case 1:
		return 1;
	case 2:
		return 2;
	default:
		BUG();
}

Using unreachable() fixes the problem.

Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 18c435d..1106439 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -89,7 +89,7 @@ extern void warn_slowpath_null(const char *file, const int line);
 
 #else /* !CONFIG_BUG */
 #ifndef HAVE_ARCH_BUG
-#define BUG() do {} while(0)
+#define BUG() unreachable() 
 #endif
 
 #ifndef HAVE_ARCH_BUG_ON
-- 
1.6.6.rc4

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