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| author |  Uros Bizjak <ubizjak@gmail.com>
| 2022-07-14 20:28:22 +0200 |
|---|---|---|
| committer |  Jason A. Donenfeld <Jason@zx2c4.com>
| 2022-07-18 15:04:04 +0200 |
| commit | b7a68f67ff4911e8a842d03f6f97fa91a8d483f5 (patch) | |
| tree | 14f878e40474fd14b5cfb224b794e8e5e1919f3f /arch/um/os-Linux | |
| parent | timekeeping: contribute wall clock to rng on time change (diff) | |
| download | linux-b7a68f67ff4911e8a842d03f6f97fa91a8d483f5.tar.gz linux-b7a68f67ff4911e8a842d03f6f97fa91a8d483f5.tar.bz2 linux-b7a68f67ff4911e8a842d03f6f97fa91a8d483f5.zip | |
random: use try_cmpxchg in _credit_init_bits
Use `!try_cmpxchg(ptr, &orig, new)` instead of `cmpxchg(ptr, orig, new)
!= orig` in _credit_init_bits. This has two benefits:
- The x86 cmpxchg instruction returns success in the ZF flag, so this
change saves a compare after cmpxchg, as well as a related move
instruction in front of cmpxchg.
- try_cmpxchg implicitly assigns the *ptr value to &orig when cmpxchg
fails, enabling further code simplifications.
This patch has no functional change.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'arch/um/os-Linux')
0 files changed, 0 insertions, 0 deletions