From: Uros Bizjak <ubizjak@gmail.com>
To: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org
Cc: Uros Bizjak <ubizjak@gmail.com>, Takashi Iwai <tiwai@suse.de>
Subject: [PATCH] ALSA: usb-audio: Use atomic_try_cmpxchg in ep_state_update
Date: Wed, 13 Jul 2022 17:19:46 +0200 [thread overview]
Message-ID: <20220713151946.4743-1-ubizjak@gmail.com> (raw)
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>
Cc: Takashi Iwai <tiwai@suse.de>
---
sound/usb/endpoint.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index f9c921683948..0d7b73bf7945 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -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);
}
/**
--
2.35.3
WARNING: multiple messages have this Message-ID (diff)
From: Uros Bizjak <ubizjak@gmail.com>
To: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org
Cc: Takashi Iwai <tiwai@suse.de>, Uros Bizjak <ubizjak@gmail.com>
Subject: [PATCH] ALSA: usb-audio: Use atomic_try_cmpxchg in ep_state_update
Date: Wed, 13 Jul 2022 17:19:46 +0200 [thread overview]
Message-ID: <20220713151946.4743-1-ubizjak@gmail.com> (raw)
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>
Cc: Takashi Iwai <tiwai@suse.de>
---
sound/usb/endpoint.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index f9c921683948..0d7b73bf7945 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -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);
}
/**
--
2.35.3
next reply other threads:[~2022-07-13 15:20 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-13 15:19 Uros Bizjak [this message]
2022-07-13 15:19 ` [PATCH] ALSA: usb-audio: Use atomic_try_cmpxchg in ep_state_update Uros Bizjak
2022-07-14 8:49 ` Takashi Iwai
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