linux-kernel - [PATCH 3.12 042/127] ARM: 8584/1: floppy: avoid gcc-6 warning

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Message-Id: <782574de6f3d5f12649c72cdb55b7ac314b6bb9c.1480062521.git.jslaby@suse.cz>
Date:   Fri, 25 Nov 2016 09:29:15 +0100
From:   Jiri Slaby <jslaby@...e.cz>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Russell King <rmk+kernel@....linux.org.uk>,
        Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 042/127] ARM: 8584/1: floppy: avoid gcc-6 warning

From: Arnd Bergmann <arnd@...db.de>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit dd665be0e243873343a28e18f9f345927b658daf upstream.

gcc-6.0 warns about comparisons between two identical expressions,
which is what we get in the floppy driver when writing to the FD_DOR
register:

drivers/block/floppy.c: In function 'set_dor':
drivers/block/floppy.c:810:44: error: self-comparison always evaluates to true [-Werror=tautological-compare]
   fd_outb(newdor, FD_DOR);

It would be nice to use a static inline function instead of the
macro, to avoid the warning, but we cannot do that because the
FD_DOR definition is incomplete at this point.

Adding a cast to (u32) is a harmless way to shut up the warning,
just not very nice.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 arch/arm/include/asm/floppy.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/floppy.h b/arch/arm/include/asm/floppy.h
index c9f03eccc9d8..b5a0466db549 100644
--- a/arch/arm/include/asm/floppy.h
+++ b/arch/arm/include/asm/floppy.h
@@ -17,7 +17,7 @@
 
 #define fd_outb(val,port)			\
 	do {					\
-		if ((port) == FD_DOR)		\
+		if ((port) == (u32)FD_DOR)	\
 			fd_setdor((val));	\
 		else				\
 			outb((val),(port));	\
-- 
2.10.2