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>
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@ -23,7 +23,8 @@ int kimage_is_destination_range(struct kimage *image,
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extern atomic_t __kexec_lock;
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extern atomic_t __kexec_lock;
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static inline bool kexec_trylock(void)
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static inline bool kexec_trylock(void)
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{
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{
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return atomic_cmpxchg_acquire(&__kexec_lock, 0, 1) == 0;
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int old = 0;
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return atomic_try_cmpxchg_acquire(&__kexec_lock, &old, 1);
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}
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}
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static inline void kexec_unlock(void)
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static inline void kexec_unlock(void)
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{
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{
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