From: Takashi Iwai <tiwai@suse.de>
Date: Sun, 23 May 2021 09:09:15 +0000 (+0200)
Subject: ALSA: core: Use READ_ONCE() / WRITE_ONCE() for power state change
X-Git-Tag: v5.14-rc1~95^2~9^2~226^2~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=533a7ed9d541674e815c7f31c933015e257df3e5;p=thirdparty%2Flinux.git

ALSA: core: Use READ_ONCE() / WRITE_ONCE() for power state change

We need proper barriers to handle the power state change of the card
from different CPUs.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210523090920.15345-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

diff --git a/include/sound/core.h b/include/sound/core.h
index 1f9aef0adbc90..d69dfc6c49535 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -142,12 +142,12 @@ struct snd_card {
 #ifdef CONFIG_PM
 static inline unsigned int snd_power_get_state(struct snd_card *card)
 {
-	return card->power_state;
+	return READ_ONCE(card->power_state);
 }
 
 static inline void snd_power_change_state(struct snd_card *card, unsigned int state)
 {
-	card->power_state = state;
+	WRITE_ONCE(card->power_state, state);
 	wake_up(&card->power_sleep);
 }