On Sat, Sep 19, 2015 at 12:42 PM, Marek Vasut <marex@xxxxxxx> wrote: > 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@xxxxxxx> > Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> > --- Tested with arch/nios2. Regards Ley Foon -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
