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authorMarek Vasut <marex@denx.de>2015-09-19 06:42:21 +0200
committerArnd Bergmann <arnd@arndb.de>2015-10-15 00:21:13 +0200
commitd975440bf80cfe4afa628141760a4a4151e58dc4 (patch)
tree95b341b63894f7ed959707586c1a5dcc3d1be166 /include/asm-generic
parent16c3bd35413126ae3e545ea5cd256c80ae755dd2 (diff)
asm-generic: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations
This change is similar to e001bbae7147b111fe1aa42beaf835635f3c016e ARM: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations A recent change in kernel/acct.c added a new warning for many configurations using generic __xchg() implementation: In file included from ./arch/nios2/include/asm/cmpxchg.h:12:0, from include/asm-generic/atomic.h:18, from arch/nios2/include/generated/asm/atomic.h:1, from include/linux/atomic.h:4, from include/linux/spinlock.h:406, from include/linux/mmzone.h:7, from include/linux/gfp.h:5, from include/linux/mm.h:9, from kernel/acct.c:46: kernel/acct.c: In function 'acct_pin_kill': include/asm-generic/cmpxchg.h:94:3: warning: value computed is not used [-Wunused-value] ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ ^ include/asm-generic/cmpxchg.h:102:28: note: in expansion of macro 'cmpxchg_local' #define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n)) ^ kernel/acct.c:177:2: note: in expansion of macro 'cmpxchg' cmpxchg(&acct->ns->bacct, pin, NULL); ^ The code is in fact correct, it's just a cmpxchg() call that intentionally ignores the result, and no other code does that. The warning does not show up on x86 because of the way that its cmpxchg() macro is written. This changes the asm-ggeneric implementation to use a similar construct with a compound expression instead of a typecast, which causes the compiler to not complain about an unused result. Fix the other macros in this file in a similar way, and place them just below their function implementations. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/cmpxchg.h11
1 files changed, 7 insertions, 4 deletions
diff --git a/include/asm-generic/cmpxchg.h b/include/asm-generic/cmpxchg.h
index 3766ab34aa45..e5f9080e8e86 100644
--- a/include/asm-generic/cmpxchg.h
+++ b/include/asm-generic/cmpxchg.h
@@ -79,8 +79,10 @@ unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
}
}
-#define xchg(ptr, x) \
- ((__typeof__(*(ptr))) __xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
+#define xchg(ptr, x) ({ \
+ ((__typeof__(*(ptr))) \
+ __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
+})
#endif /* xchg */
@@ -90,9 +92,10 @@ unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
#include <asm-generic/cmpxchg-local.h>
#ifndef cmpxchg_local
-#define cmpxchg_local(ptr, o, n) \
+#define cmpxchg_local(ptr, o, n) ({ \
((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
- (unsigned long)(n), sizeof(*(ptr))))
+ (unsigned long)(n), sizeof(*(ptr)))); \
+})
#endif
#ifndef cmpxchg64_local

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