linux-kernel - [PATCH 3.18 026/145] ARM: 8584/1: floppy: avoid gcc-6 warning

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Date:   Sun, 16 Apr 2017 12:48:39 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Russell King <rmk+kernel@....linux.org.uk>
Subject: [PATCH 3.18 026/145] ARM: 8584/1: floppy: avoid gcc-6 warning

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

------------------

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

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: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm/include/asm/floppy.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 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));	\