[mmotm] "x86/atomic: move __arch_atomic_add_unless out of line" build error

[Sergey Senozhatsky]

Hello,

commit 4f86a82ff7df ("x86/atomic: move __arch_atomic_add_unless out of line")
moved __arch_atomic_add_unless() out atomic.h and new KASAN atomic
instrumentation [1] can't see it anymore


In file included from ./arch/x86/include/asm/atomic.h:257:0,
                 from ./include/linux/atomic.h:4,
                 from ./include/asm-generic/qspinlock_types.h:28,
                 from ./arch/x86/include/asm/spinlock_types.h:26,
                 from ./include/linux/spinlock_types.h:13,
                 from kernel/bounds.c:13:
./include/asm-generic/atomic-instrumented.h: In function â__atomic_add_unlessâ:
./include/asm-generic/atomic-instrumented.h:70:9: error: implicit declaration of function â__arch_atomic_add_unlessâ [-Werror=implicit-function-declaration]
  return __arch_atomic_add_unless(v, a, u);
         ^~~~~~~~~~~~~~~~~~~~~~~~


so we need a declaration of __arch_atomic_add_unless() in arch/x86/include/asm/atomic.h


[1] lkml.kernel.org/r/7e450175a324bf93c602909c711bc34715d8e8f2.1489519233.git.dvyukov@xxxxxxxxxx

	-ss