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
Fixes: 209c6cdfd283 ("ASoC: soc-card: move snd_soc_card_get_kcontrol() to
soc-card")
---
It would be great if people could test the fsl/, qcom/, ti/rx51 and ak4418
drivers.
---
include/sound/soc-card.h | 2 ++
sound/soc/codecs/cs35l45.c | 2 +-
sound/soc/codecs/cs35l56.c | 2 +-
sound/soc/fsl/fsl_xcvr.c | 12 +++-
sound/soc/soc-card.c | 24 ++--
5 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/include/sound/soc-card.h b/include/sound/soc-card.h
index ecc02e955279..1f4c39922d82 100644
--- a/include/sound/soc-card.h
+++ b/include/sound/soc-card.h
@@ -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,
diff --git a/sound/soc/codecs/cs35l45.c b/sound/soc/codecs/cs35l45.c
index 44c221745c3b..2392c6effed8 100644
--- a/sound/soc/codecs/cs35l45.c
+++ b/sound/soc/codecs/cs35l45.c
@@ -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;
diff --git a/sound/soc/codecs/cs35l56.c b/sound/soc/codecs/cs35l56.c
index 2c1313e34cce..6dd0319bc843 100644
--- a/sound/soc/codecs/cs35l56.c
+++ b/sound/soc/codecs/cs35l56.c
@@ -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);
