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| author | Uros Bizjak <ubizjak@gmail.com> | 2024-07-19 12:38:52 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-01 20:43:23 -0700 |
| commit | acf02be3c72f12c31f916d3465c4c716b4729538 (patch) | |
| tree | 9f247e7a5d880e4f6d20a108c7c68680d7545b0f /kernel/kexec_internal.h | |
| parent | e24f4de8a72b50b67ea116b38152bb98360f81b3 (diff) | |
| download | lwn-acf02be3c72f12c31f916d3465c4c716b4729538.tar.gz lwn-acf02be3c72f12c31f916d3465c4c716b4729538.zip | |
kexec: use atomic_try_cmpxchg_acquire() in kexec_trylock()
Use atomic_try_cmpxchg_acquire(*ptr, &old, new) instead of
atomic_cmpxchg_acquire(*ptr, old, new) == old in kexec_trylock().
x86 CMPXCHG instruction returns success in ZF flag, so
this change saves a compare after cmpxchg.
Link: https://lkml.kernel.org/r/20240719103937.53742-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel/kexec_internal.h')
| -rw-r--r-- | kernel/kexec_internal.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h index 2595defe8c0d..d35d9792402d 100644 --- a/kernel/kexec_internal.h +++ b/kernel/kexec_internal.h @@ -23,7 +23,8 @@ int kimage_is_destination_range(struct kimage *image, extern atomic_t __kexec_lock; static inline bool kexec_trylock(void) { - return atomic_cmpxchg_acquire(&__kexec_lock, 0, 1) == 0; + int old = 0; + return atomic_try_cmpxchg_acquire(&__kexec_lock, &old, 1); } static inline void kexec_unlock(void) { |