Dne 21. 02. 21 v 14:14 Hans de Goede napsal(a):
>> v2 changes:
>> - fix the locking - remove the controls_rwsem read lock
>> in the element get (the consistency is already protected
>> with the global snd_ctl_led_mutex and possible partial
>> value writes are catched with the next value change
>> notification callback)
>
> I'm afraid that lockdep still is unhappy. With v2 there is a new
> (different) lockdep warning.
> If you can send me another fixup-diff then I'll make sure to
> test this before you do a v3, so that we can be sure that
> all cases which my setup catches are resolved before sending
> out v3.
Thank you for your test. This change (on top of v2) should resolve this
remaining lockdep:
diff --git a/sound/core/control.c b/sound/core/control.c
index c9f062fada0a..494f0154e8be 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -2051,7 +2051,9 @@ void snd_ctl_register_layer(struct snd_ctl_layer_ops *lops)
for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
card = snd_card_ref(card_number);
if (card) {
+ down_read(&card->controls_rwsem);
lops->lregister(card);
+ up_read(&card->controls_rwsem);
snd_card_unref(card);
}
}
@@ -2113,10 +2115,12 @@ static int snd_ctl_dev_register(struct snd_device *device)
&snd_ctl_f_ops, card, &card->ctl_dev);
if (err < 0)
return err;
+ down_read(&card->controls_rwsem);
down_read(&snd_ctl_layer_rwsem);
for (lops = snd_ctl_layer; lops; lops = lops->next)
lops->lregister(card);
up_read(&snd_ctl_layer_rwsem);
+ up_read(&card->controls_rwsem);
return 0;
}
@@ -2137,10 +2141,12 @@ static int snd_ctl_dev_disconnect(struct snd_device
*device)
}
read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
+ down_read(&card->controls_rwsem);
down_read(&snd_ctl_layer_rwsem);
for (lops = snd_ctl_layer; lops; lops = lops->next)
lops->ldisconnect(card);
up_read(&snd_ctl_layer_rwsem);
+ up_read(&card->controls_rwsem);
return snd_unregister_device(&card->ctl_dev);
}
diff --git a/sound/core/control_led.c b/sound/core/control_led.c
index cafe4c82ca35..b8bb8fd46686 100644
--- a/sound/core/control_led.c
+++ b/sound/core/control_led.c
@@ -235,11 +235,10 @@ static void snd_ctl_led_register(struct snd_card *card)
mutex_lock(&snd_ctl_led_mutex);
snd_ctl_led_card_valid[card->number] = true;
mutex_unlock(&snd_ctl_led_mutex);
- down_read(&card->controls_rwsem);
+ /* the register callback is already called with held card->controls_rwsem */
list_for_each_entry(kctl, &card->controls, list)
for (ioff = 0; ioff < kctl->count; ioff++)
snd_ctl_led_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, ioff);
- up_read(&card->controls_rwsem);
snd_ctl_led_refresh();
}
Jaroslav
--
Jaroslav Kysela <perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
