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ALSA: usb-audio: Use atomic_try_cmpxchg in ep_state_update 

Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old in
ep_state_update. x86 CMPXCHG instruction returns success in ZF flag,
so this change saves a compare after cmpxchg (and related move instruction
in front of cmpxchg).

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20220713151946.4743-1-ubizjak@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Uros Bizjak 2022-07-13 17:19:46 +02:00 committed by Takashi Iwai
parent 281dee6707
commit 89422df954
1 changed files with 1 additions and 1 deletions
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2
sound/usb/endpoint.c
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@ -133,7 +133,7 @@ static inline bool ep_state_running(struct snd_usb_endpoint *ep)
static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
{
return atomic_cmpxchg(&ep->state, old, new) == old;
return atomic_try_cmpxchg(&ep->state, &old, new);
}
/**