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| author | Uros Bizjak <ubizjak@gmail.com> | 2022-08-22 16:38:51 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-09-11 21:55:09 -0700 |
| commit | e1d7c7609ae0933b59840390c1b207ac0a925c8b (patch) | |
| tree | 55170982bc11f6e761a136a01649c1ccc5e92d1b /include/linux/tty_port.h | |
| parent | 21490eff121555b123f7088b935e40ee43d2c642 (diff) | |
bitops: use try_cmpxchg in set_mask_bits and bit_clear_unless
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
set_mask_bits and bit_clear_unless. x86 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, enabling further code simplifications.
Link: https://lkml.kernel.org/r/20220822143851.3290-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/tty_port.h')
0 files changed, 0 insertions, 0 deletions