kernel/linux.git/include/sound/core.h, branch v6.6.131

ALSA: core: Drop snd_device_initialize()

2023-08-17T07:24:33+00:00

Now all users of snd_device_intialize() are gone, let's drop it. Reviewed-by: Jaroslav Kysela Signed-off-by: Curtis Malainey Tested-by: Curtis Malainey Link: https://lore.kernel.org/r/20230816160252.23396-10-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: control: Don't embed ctl_dev

2023-08-17T07:23:30+00:00

Embedding the ctl_dev in the snd_card object may result in UAF when the delayed kobj release is used; at the delayed kobj release, it still accesses the struct device itself while the card memory (that embeds the struct device) may be already gone. As a workaround, detach the struct device from the card object by allocating via the new snd_device_alloc() helper. The rest are just replacing ctl_dev access to the pointer. This is based on the fix Curtis posted initially. In this patch, the changes are split and use the new helper function instead. Link: https://lore.kernel.org/r/20230801171928.1460120-1-cujomalainey@chromium.org Reviewed-by: Jaroslav Kysela Signed-off-by: Curtis Malainey Tested-by: Curtis Malainey Link: https://lore.kernel.org/r/20230816160252.23396-3-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: core: Introduce snd_device_alloc()

2023-08-17T07:21:40+00:00

Introduce a new helper, snd_device_alloc(), for allocating a struct device that is bound with the sound class. It's a replacement of snd_device_initialize(). Reviewed-by: Jaroslav Kysela Signed-off-by: Curtis Malainey Tested-by: Curtis Malainey Link: https://lore.kernel.org/r/20230816160252.23396-2-tiwai@suse.de Signed-off-by: Takashi Iwai

sound: make all 'class' structures const

2023-06-21T05:29:10+00:00

Now that the driver core allows for struct class to be in read-only memory, making all 'class' structures to be declared at build time placing them into read-only memory, instead of having to be dynamically allocated at load time. Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Ivan Orlov Cc: Greg Kroah-Hartman Cc: Geoff Levand Cc: Thierry Reding Cc: "Uwe Kleine-König" Cc: alsa-devel@alsa-project.org Suggested-by: Greg Kroah-Hartman Signed-off-by: Ivan Orlov Signed-off-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20230620175633.641141-2-gregkh@linuxfoundation.org Signed-off-by: Takashi Iwai

ALSA: core: update comment on snd_card.controls_rwsem

2023-05-08T07:25:48+00:00

Since commit 5bbb1ab5bd ("control: use counting semaphore as write lock for ELEM_WRITE operation"), this has been locking the controls including their values, not just the list of controls. Signed-off-by: Oswald Buddenhagen Link: https://lore.kernel.org/r/20230428095941.1706278-6-oswald.buddenhagen@gmx.de Signed-off-by: Takashi Iwai

ALSA: core: Make snd_card_free() return void

2023-02-08T12:39:27+00:00

The function returns 0 unconditionally. Make it return void instead and simplify all callers accordingly. Signed-off-by: Uwe Kleine-König Reviewed-by: Jaroslav Kysela Reviewed-by: Takashi Sakamoto Acked-by: Geoff Levand Acked-by: Thierry Reding Link: https://lore.kernel.org/r/20230207191907.467756-4-u.kleine-koenig@pengutronix.de Signed-off-by: Takashi Iwai

ALSA: core: Make snd_card_free_when_closed() return void

2023-02-08T12:39:12+00:00

All callers from other files ignore the return value of this function. And it can only ever return a non-zero value if the parameter card is NULL. This cannot happen in snd_card_free() as card was dereferenced just before snd_card_free_when_closed() is called. So the error handling can be dropped there. Signed-off-by: Uwe Kleine-König Reviewed-by: Jaroslav Kysela Reviewed-by: Takashi Sakamoto Acked-by: Geoff Levand Acked-by: Thierry Reding Link: https://lore.kernel.org/r/20230207191907.467756-3-u.kleine-koenig@pengutronix.de Signed-off-by: Takashi Iwai

ALSA: core: Make snd_card_disconnect() return void

2023-02-08T12:38:28+00:00

All callers from other files ignore the return value of this function. And it can only ever return a non-zero value if the parameter card is NULL. Move the check for card being NULL into snd_card_free_when_closed() to keep the previous behaviour. Note this isn't necessary for snd_card_disconnect_sync() because if card was NULL in there the dereference of card for dev_err() would oops the kernel. Replace this by an oops triggered by the dereference of card for spin_lock_irq(). Signed-off-by: Uwe Kleine-König Reviewed-by: Jaroslav Kysela Reviewed-by: Takashi Sakamoto Acked-by: Geoff Levand Acked-by: Thierry Reding Link: https://lore.kernel.org/r/20230207191907.467756-2-u.kleine-koenig@pengutronix.de Signed-off-by: Takashi Iwai

ALSA: core: Add async signal helpers

2022-07-29T10:57:10+00:00

Currently the call of kill_fasync() from an interrupt handler might lead to potential spin deadlocks, as spotted by syzkaller. Unfortunately, it's not so trivial to fix this lock chain as it's involved with the tasklist_lock that is touched in allover places. As a temporary workaround, this patch provides the way to defer the async signal notification in a work. The new helper functions, snd_fasync_helper() and snd_kill_faync() are replacements for fasync_helper() and kill_fasync(), respectively. In addition, snd_fasync_free() needs to be called at the destructor of the relevant file object. Link: https://lore.kernel.org/r/20220728125945.29533-2-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: control: Use xarray for faster lookups

2022-06-15T05:44:55+00:00

The control elements are managed in a single linked list and we traverse the whole list for matching each numid or ctl id per every inquiry of a control element. This is OK-ish for a small number of elements but obviously it doesn't scale. Especially the matching with the ctl id takes time because it checks each field of the snd_ctl_id element, e.g. the name string is matched with strcmp(). This patch adds the hash tables with Xarray for improving the lookup speed of a control element. There are two xarray tables added to the card; one for numid and another for ctl id. For the numid, we use the numid as the index, while for the ctl id, we calculate a hash key. The lookup is done via a single xa_load() execution. As long as the given control element is found on the Xarray table, that's fine, we can give back a quick lookup result. The problem is when no entry hits on the table, and for this case, we have a slight optimization. Namely, the driver checks whether we had a collision on Xarray table, and do a fallback search (linear lookup of the full entries) only if a hash key collision happened beforehand. So, in theory, the inquiry for a non-existing element might take still time even with this patch in a worst case, but this must be pretty rare. The feature is enabled via CONFIG_SND_CTL_FAST_LOOKUP, which is turned on as default. For simplicity, the option can be turned off only when CONFIG_EXPERT is set ("You are expert? Then you manage 1000 knobs"). Link: https://lore.kernel.org/r/20211028130027.18764-1-tiwai@suse.de Link: https://lore.kernel.org/r/20220609180504.775-1-tiwai@suse.de Link: https://lore.kernel.org/all/cover.1653813866.git.quic_rbankapu@quicinc.com/ Link: https://lore.kernel.org/r/20220610064537.18660-1-tiwai@suse.de Signed-off-by: Takashi Iwai