[00/11] ALSA: Make control API taking controls_rwsem consistently

Message

Takashi Iwai July 18, 2023, 2:12 p.m. UTC

A few ALSA control API helpers like snd_ctl_rename(), snd_ctl_remove()
and snd_ctl_find_*() suppose the callers taking card->controls_rwsem.
But it's error-prone and fragile.  This patch set tries to change
those API functions to take the card->controls>rwsem internally by
themselves, so that the drivers don't need to take care of lockings.

After applying this patch set, only a couple of places still touch
card->controls_rwsem (which are OK-ish as they need for traversing the
control linked list).


Takashi

===

Takashi Iwai (11):
  ALSA: control: Take card->controls_rwsem in snd_ctl_rename()
  staging: greybus: audio_helper: Use snd_ctl_remove_id()
  ASoC: atmel: mchp-pdmc: Use snd_ctl_remove_id()
  ALSA: control: Take controls_rwsem lock in snd_ctl_remove()
  ALSA: control: Add lockdep warning to internal functions
  ASoC: sigmadsp: Simplify with snd_ctl_activate_id()
  staging: greybus: Avoid abusing controls_rwsem
  ALSA: control: Make snd_ctl_find_id() argument const
  ALSA: control: Introduce unlocked version for snd_ctl_find_*() helpers
  ALSA: control: Take lock in snd_ctl_find_id() and snd_ctl_find_numid()
  ALSA: emu10k1: Go back and simplify with snd_ctl_find_id()

 drivers/staging/greybus/audio_codec.c  |  18 ++--
 drivers/staging/greybus/audio_codec.h  |   1 +
 drivers/staging/greybus/audio_helper.c |  20 +---
 include/sound/control.h                |   6 +-
 sound/core/control.c                   | 126 ++++++++++++++++++++-----
 sound/core/control_compat.c            |   2 +-
 sound/core/control_led.c               |   2 +-
 sound/core/jack.c                      |   2 -
 sound/core/oss/mixer_oss.c             |  10 +-
 sound/core/pcm.c                       |   2 -
 sound/isa/sb/emu8000.c                 |   2 -
 sound/isa/sb/sb16_csp.c                |   2 -
 sound/pci/emu10k1/emufx.c              |   5 -
 sound/pci/hda/hda_codec.c              |   2 -
 sound/soc/atmel/mchp-pdmc.c            |  12 +--
 sound/soc/codecs/sigmadsp.c            |  25 +----
 sound/soc/soc-topology.c               |   3 -
 17 files changed, 129 insertions(+), 111 deletions(-)

Comments

Takashi Iwai July 20, 2023, 8:16 a.m. UTC | #1

On Tue, 18 Jul 2023 16:12:53 +0200,
Takashi Iwai wrote:
> 
> A few ALSA control API helpers like snd_ctl_rename(), snd_ctl_remove()
> and snd_ctl_find_*() suppose the callers taking card->controls_rwsem.
> But it's error-prone and fragile.  This patch set tries to change
> those API functions to take the card->controls>rwsem internally by
> themselves, so that the drivers don't need to take care of lockings.
> 
> After applying this patch set, only a couple of places still touch
> card->controls_rwsem (which are OK-ish as they need for traversing the
> control linked list).
> 
> 
> Takashi
> 
> ===
> 
> Takashi Iwai (11):
>   ALSA: control: Take card->controls_rwsem in snd_ctl_rename()
>   staging: greybus: audio_helper: Use snd_ctl_remove_id()
>   ASoC: atmel: mchp-pdmc: Use snd_ctl_remove_id()
>   ALSA: control: Take controls_rwsem lock in snd_ctl_remove()
>   ALSA: control: Add lockdep warning to internal functions
>   ASoC: sigmadsp: Simplify with snd_ctl_activate_id()
>   staging: greybus: Avoid abusing controls_rwsem
>   ALSA: control: Make snd_ctl_find_id() argument const
>   ALSA: control: Introduce unlocked version for snd_ctl_find_*() helpers
>   ALSA: control: Take lock in snd_ctl_find_id() and snd_ctl_find_numid()
>   ALSA: emu10k1: Go back and simplify with snd_ctl_find_id()

Now all merged.  The branch is based on 6.5-rc2, and tagged as
ctl-lock-fixes-6.6 so that other branch can merge this if needed.


Takashi