build warning on v4.0-rc1

From: Felipe Balbi
Date: Wed Feb 25 2015 - 12:52:33 EST


Hi Al,

commit 3b994d98a815d934ab6a77a380882865982c14f9 (get rid of the second
argument of acct_kill()) added a new build warning when building
kernel/acct.c. Warning can be seen below. Revert of that commit is
non-trivial, so I haven't tried to check if reverting it fixes the
warning.

One one to silent the warning would be to cast return of cmpxchg to void
on the call inside acct_pin_kill(), but maybe there's a better way?

In file included from ./arch/arm/include/asm/atomic.h:19:0,
from include/linux/atomic.h:4,
from include/linux/debug_locks.h:5,
from include/linux/lockdep.h:23,
from include/linux/spinlock_types.h:18,
from include/linux/spinlock.h:81,
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 âacct_killâ:
./arch/arm/include/asm/cmpxchg.h:205:3: warning: value computed is not used [-Wunused-value]
((__typeof__(*(ptr)))__cmpxchg_mb((ptr), \
^
kernel/acct.c:181:3: note: in expansion of macro âcmpxchgâ
cmpxchg(&ns->bacct, acct, NULL);
^

cheers

--
balbi

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