In commit d0563a1297 ("powerpc: Implement {cmp}xchg for u8 and u16")
we removed the volatile from __cmpxchg().
This is leading to warnings such as:
drivers/gpu/drm/drm_lock.c: In function ‘drm_lock_take’:
arch/powerpc/include/asm/cmpxchg.h:484:37: warning: passing argument 1
of ‘__cmpxchg’ discards ‘volatile’ qualifier from pointer target
(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
There doesn't seem to be consensus across architectures whether the
argument is volatile or not, so at least for now put the volatile back.
Fixes: d0563a1297 ("powerpc: Implement {cmp}xchg for u8 and u16")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
da58b23cb9