3.16.61-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Takashi Iwai tiwai@suse.de
commit dc82e52492f684dcd5ed9e4773e72dbf2203d75e upstream.
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 Signed-off-by: Ben Hutchings ben@decadent.org.uk --- include/sound/core.h | 2 +- sound/core/device.c | 9 +++++++++ 2 files changed, 10 insertions(+), 1 deletion(-)
--- 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 { --- a/sound/core/device.c +++ b/sound/core/device.c @@ -219,6 +219,15 @@ void snd_device_free_all(struct snd_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); }