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authorTakashi Iwai <tiwai@suse.de>2018-05-15 20:25:29 +0200
committerTakashi Iwai <tiwai@suse.de>2018-05-17 08:21:23 +0200
commitdc82e52492f684dcd5ed9e4773e72dbf2203d75e (patch)
tree7dd4a15e2d6a8c038c5c66bdb533dfaa549eed8c
parent377a879d9832f4ba69bd6a1fc996bb4181b1e504 (diff)
downloadlinux-dc82e52492f684dcd5ed9e4773e72dbf2203d75e.tar.bz2
ALSA: core: Assure control device to be registered at last
The commit 289ca025ee1d ("ALSA: Use priority list for managing device list") changed the way to register/disconnect/free devices via a single priority list. This helped to make behavior consistent, but it also changed a slight behavior change: namely, the control device is registered earlier than others, while it was supposed to be the very last one. I've put SNDRV_DEV_CONTROL in the current position as the release of ctl elements often conflict with the private ctl elements some PCM or other components may create, which often leads to a double-free. But, the order of register and disconnect should be indeed fixed as expected in the early days: the control device gets registered at last, and disconnected at first. This patch changes the priority list order to move SNDRV_DEV_CONTROL as the last guy to assure the register / disconnect order. Meanwhile, for keeping the messy resource release order, manually treat the control and lowlevel devices as last freed one. Additional note: The lowlevel device is the device where a card driver creates at probe. And, we still keep the release order control -> lowlevel, as there might be link from a control element back to a lowlevel object. Fixes: 289ca025ee1d ("ALSA: Use priority list for managing device list") Reported-by: Tzung-Bi Shih <tzungbi@google.com> Tested-by: Tzung-Bi Shih <tzungbi@google.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--include/sound/core.h2
-rw-r--r--sound/core/device.c9
2 files changed, 10 insertions, 1 deletions
diff --git a/include/sound/core.h b/include/sound/core.h
index 5f181b875c2f..36a5934cf4b1 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -51,7 +51,6 @@ struct completion;
*/
enum snd_device_type {
SNDRV_DEV_LOWLEVEL,
- SNDRV_DEV_CONTROL,
SNDRV_DEV_INFO,
SNDRV_DEV_BUS,
SNDRV_DEV_CODEC,
@@ -62,6 +61,7 @@ enum snd_device_type {
SNDRV_DEV_SEQUENCER,
SNDRV_DEV_HWDEP,
SNDRV_DEV_JACK,
+ SNDRV_DEV_CONTROL, /* NOTE: this must be the last one */
};
enum snd_device_state {
diff --git a/sound/core/device.c b/sound/core/device.c
index cb0e46f66cc9..535102d564e3 100644
--- a/sound/core/device.c
+++ b/sound/core/device.c
@@ -240,6 +240,15 @@ void snd_device_free_all(struct snd_card *card)
if (snd_BUG_ON(!card))
return;
+ list_for_each_entry_safe_reverse(dev, next, &card->devices, list) {
+ /* exception: free ctl and lowlevel stuff later */
+ if (dev->type == SNDRV_DEV_CONTROL ||
+ dev->type == SNDRV_DEV_LOWLEVEL)
+ continue;
+ __snd_device_free(dev);
+ }
+
+ /* free all */
list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
__snd_device_free(dev);
}