mm/rmap: use atomic_try_cmpxchg in set_tlb_ubc_flush_pending
Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old
in set_tlb_ubc_flush_pending. 86 CMPXCHG instruction returns success in
ZF flag, so this change saves a compare after cmpxchg (and related move
instruction in front of cmpxchg).
Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails.
No functional change intended.
Link: https://lkml.kernel.org/r/20230227214228.3533299-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>