ASoC: soc-card: Fix missing locking in snd_soc_card_get_kcontrol()

snd_soc_card_get_kcontrol() must be holding a read lock on
card->controls_rwsem while walking the controls list.

Compare with snd_ctl_find_numid().

The existing function is renamed snd_soc_card_get_kcontrol_locked()
so that it can be called from contexts that are already holding
card->controls_rwsem (for example, control get/put functions).

There are few direct or indirect callers of
snd_soc_card_get_kcontrol(), and most are safe. Three require
changes, which have been included in this patch:

codecs/cs35l45.c:
  cs35l45_activate_ctl() is called from a control put() function so
  is changed to call snd_soc_card_get_kcontrol_locked().

codecs/cs35l56.c:
  cs35l56_sync_asp1_mixer_widgets_with_firmware() is called from
  control get()/put() functions so is changed to call
  snd_soc_card_get_kcontrol_locked().

fsl/fsl_xcvr.c:
  fsl_xcvr_activate_ctl() is called from three places, one of which
  already holds card->controls_rwsem:
  1. fsl_xcvr_mode_put(), a control put function, which will
     already be holding card->controls_rwsem.
  2. fsl_xcvr_startup(), a DAI startup function.
  3. fsl_xcvr_shutdown(), a DAI shutdown function.

  To fix this, fsl_xcvr_activate_ctl() has been changed to call
  snd_soc_card_get_kcontrol_locked() so that it is safe to call
  directly from fsl_xcvr_mode_put().
  The fsl_xcvr_startup() and fsl_xcvr_shutdown() functions have been
  changed to take a read lock on card->controls_rsem() around calls
  to fsl_xcvr_activate_ctl(). While this is not very elegant, it
  keeps the change small, to avoid this patch creating a large
  collateral churn in fsl/fsl_xcvr.c.

Analysis of other callers of snd_soc_card_get_kcontrol() is that
they do not need any changes, they are not holding card->controls_rwsem
when they call snd_soc_card_get_kcontrol().

Direct callers of snd_soc_card_get_kcontrol():
  fsl/fsl_spdif.c: fsl_spdif_dai_probe() - DAI probe function
  fsl/fsl_micfil.c: voice_detected_fn() - IRQ handler

Indirect callers via soc_component_notify_control():
  codecs/cs42l43: cs42l43_mic_shutter() - IRQ handler
  codecs/cs42l43: cs42l43_spk_shutter() - IRQ handler
  codecs/ak4118.c: ak4118_irq_handler() - IRQ handler
  codecs/wm_adsp.c: wm_adsp_write_ctl() - not currently used

Indirect callers via snd_soc_limit_volume():
  qcom/sc8280xp.c: sc8280xp_snd_init() - DAIlink init function
  ti/rx51.c: rx51_aic34_init() - DAI init function

I don't have hardware to test the fsl/*, qcom/sc828xp.c, ti/rx51.c
and ak4118.c changes.

Backport note:
The fsl/, qcom/, cs35l45, cs35l56 and cs42l43 callers were added
since the Fixes commit so won't all be present on older kernels.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: 209c6cdfd2 ("ASoC: soc-card: move snd_soc_card_get_kcontrol() to soc-card")
Link: https://lore.kernel.org/r/20240221123710.690224-1-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Richard Fitzgerald 2024-02-21 12:37:10 +00:00 committed by Mark Brown
parent 1382d8b551
commit eba2eb2495
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
5 changed files with 37 additions and 5 deletions

View file

@ -30,6 +30,8 @@ static inline void snd_soc_card_mutex_unlock(struct snd_soc_card *card)
struct snd_kcontrol *snd_soc_card_get_kcontrol(struct snd_soc_card *soc_card,
const char *name);
struct snd_kcontrol *snd_soc_card_get_kcontrol_locked(struct snd_soc_card *soc_card,
const char *name);
int snd_soc_card_jack_new(struct snd_soc_card *card, const char *id, int type,
struct snd_soc_jack *jack);
int snd_soc_card_jack_new_pins(struct snd_soc_card *card, const char *id,

View file

@ -184,7 +184,7 @@ static int cs35l45_activate_ctl(struct snd_soc_component *component,
else
snprintf(name, SNDRV_CTL_ELEM_ID_NAME_MAXLEN, "%s", ctl_name);
kcontrol = snd_soc_card_get_kcontrol(component->card, name);
kcontrol = snd_soc_card_get_kcontrol_locked(component->card, name);
if (!kcontrol) {
dev_err(component->dev, "Can't find kcontrol %s\n", name);
return -EINVAL;

View file

@ -114,7 +114,7 @@ static int cs35l56_sync_asp1_mixer_widgets_with_firmware(struct cs35l56_private
name = full_name;
}
kcontrol = snd_soc_card_get_kcontrol(dapm->card, name);
kcontrol = snd_soc_card_get_kcontrol_locked(dapm->card, name);
if (!kcontrol) {
dev_warn(cs35l56->base.dev, "Could not find control %s\n", name);
continue;

View file

@ -174,7 +174,9 @@ static int fsl_xcvr_activate_ctl(struct snd_soc_dai *dai, const char *name,
struct snd_kcontrol *kctl;
bool enabled;
kctl = snd_soc_card_get_kcontrol(card, name);
lockdep_assert_held(&card->snd_card->controls_rwsem);
kctl = snd_soc_card_get_kcontrol_locked(card, name);
if (kctl == NULL)
return -ENOENT;
@ -576,10 +578,14 @@ static int fsl_xcvr_startup(struct snd_pcm_substream *substream,
xcvr->streams |= BIT(substream->stream);
if (!xcvr->soc_data->spdif_only) {
struct snd_soc_card *card = dai->component->card;
/* Disable XCVR controls if there is stream started */
down_read(&card->snd_card->controls_rwsem);
fsl_xcvr_activate_ctl(dai, fsl_xcvr_mode_kctl.name, false);
fsl_xcvr_activate_ctl(dai, fsl_xcvr_arc_mode_kctl.name, false);
fsl_xcvr_activate_ctl(dai, fsl_xcvr_earc_capds_kctl.name, false);
up_read(&card->snd_card->controls_rwsem);
}
return 0;
@ -598,11 +604,15 @@ static void fsl_xcvr_shutdown(struct snd_pcm_substream *substream,
/* Enable XCVR controls if there is no stream started */
if (!xcvr->streams) {
if (!xcvr->soc_data->spdif_only) {
struct snd_soc_card *card = dai->component->card;
down_read(&card->snd_card->controls_rwsem);
fsl_xcvr_activate_ctl(dai, fsl_xcvr_mode_kctl.name, true);
fsl_xcvr_activate_ctl(dai, fsl_xcvr_arc_mode_kctl.name,
(xcvr->mode == FSL_XCVR_MODE_ARC));
fsl_xcvr_activate_ctl(dai, fsl_xcvr_earc_capds_kctl.name,
(xcvr->mode == FSL_XCVR_MODE_EARC));
up_read(&card->snd_card->controls_rwsem);
}
ret = regmap_update_bits(xcvr->regmap, FSL_XCVR_EXT_IER0,
FSL_XCVR_IRQ_EARC_ALL, 0);

View file

@ -5,6 +5,9 @@
// Copyright (C) 2019 Renesas Electronics Corp.
// Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
//
#include <linux/lockdep.h>
#include <linux/rwsem.h>
#include <sound/soc.h>
#include <sound/jack.h>
@ -26,12 +29,15 @@ static inline int _soc_card_ret(struct snd_soc_card *card,
return ret;
}
struct snd_kcontrol *snd_soc_card_get_kcontrol(struct snd_soc_card *soc_card,
const char *name)
struct snd_kcontrol *snd_soc_card_get_kcontrol_locked(struct snd_soc_card *soc_card,
const char *name)
{
struct snd_card *card = soc_card->snd_card;
struct snd_kcontrol *kctl;
/* must be held read or write */
lockdep_assert_held(&card->controls_rwsem);
if (unlikely(!name))
return NULL;
@ -40,6 +46,20 @@ struct snd_kcontrol *snd_soc_card_get_kcontrol(struct snd_soc_card *soc_card,
return kctl;
return NULL;
}
EXPORT_SYMBOL_GPL(snd_soc_card_get_kcontrol_locked);
struct snd_kcontrol *snd_soc_card_get_kcontrol(struct snd_soc_card *soc_card,
const char *name)
{
struct snd_card *card = soc_card->snd_card;
struct snd_kcontrol *kctl;
down_read(&card->controls_rwsem);
kctl = snd_soc_card_get_kcontrol_locked(soc_card, name);
up_read(&card->controls_rwsem);
return kctl;
}
EXPORT_SYMBOL_GPL(snd_soc_card_get_kcontrol);
static int jack_new(struct snd_soc_card *card, const char *id, int type,