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Message-ID: <s5h7g936ru1.wl%tiwai@suse.de>
Date: Mon, 10 Feb 2014 14:05:26 +0100
From: Takashi Iwai <tiwai@...e.de>
To: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
Cc: broonie@...nel.org, alsa-devel@...a-project.org,
patches@...nsource.wolfsonmicro.com, dmitry.torokhov@...il.com,
lgirdwood@...il.com, linux-kernel@...r.kernel.org,
cw00.choi@...sung.com, myungjoo.ham@...sung.com
Subject: Re: [alsa-devel] [PATCH] ASoC: dapm: Add locking to snd_soc_dapm_xxxx_pin functions
At Mon, 10 Feb 2014 11:05:36 +0000,
Charles Keepax wrote:
>
> snd_soc_dapm_disable_pin, snd_soc_dapm_enable_pin and
> snd_soc_dapm_force_enable_pin all require the dapm_mutex to be held when
> they are called as they edit the dirty list. There are 385 usages of
> these functions and only 7 hold the lock whilst calling.
>
> This patch moves the locking into snd_soc_dapm_set_pin and fixes up the
> places where the lock was held on the caller side. This saves on fixing
> up all the current users and also is much more consistant with the rest
> of the DAPM API which all handles the locking internally.
>
> Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
> ---
>
> Hi,
>
> I have put the changes in a single patch to avoid bisect
> problems, but let me know if it would be better split into
> seperate patches.
>
> Thanks,
> Charles
>
> drivers/extcon/extcon-arizona.c | 11 -----------
> drivers/input/misc/arizona-haptics.c | 19 -------------------
> sound/soc/soc-dapm.c | 8 ++++----
> 3 files changed, 4 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/extcon/extcon-arizona.c b/drivers/extcon/extcon-arizona.c
> index c20602f..84167f4 100644
> --- a/drivers/extcon/extcon-arizona.c
> +++ b/drivers/extcon/extcon-arizona.c
> @@ -222,26 +222,19 @@ static void arizona_extcon_pulse_micbias(struct arizona_extcon_info *info)
> struct snd_soc_dapm_context *dapm = arizona->dapm;
> int ret;
>
> - mutex_lock(&dapm->card->dapm_mutex);
> -
> ret = snd_soc_dapm_force_enable_pin(dapm, widget);
> if (ret != 0)
> dev_warn(arizona->dev, "Failed to enable %s: %d\n",
> widget, ret);
>
> - mutex_unlock(&dapm->card->dapm_mutex);
> -
> snd_soc_dapm_sync(dapm);
>
> if (!arizona->pdata.micd_force_micbias) {
> - mutex_lock(&dapm->card->dapm_mutex);
> -
> ret = snd_soc_dapm_disable_pin(arizona->dapm, widget);
> if (ret != 0)
> dev_warn(arizona->dev, "Failed to disable %s: %d\n",
> widget, ret);
>
> - mutex_unlock(&dapm->card->dapm_mutex);
>
> snd_soc_dapm_sync(dapm);
> }
> @@ -304,16 +297,12 @@ static void arizona_stop_mic(struct arizona_extcon_info *info)
> ARIZONA_MICD_ENA, 0,
> &change);
>
> - mutex_lock(&dapm->card->dapm_mutex);
> -
> ret = snd_soc_dapm_disable_pin(dapm, widget);
> if (ret != 0)
> dev_warn(arizona->dev,
> "Failed to disable %s: %d\n",
> widget, ret);
>
> - mutex_unlock(&dapm->card->dapm_mutex);
> -
> snd_soc_dapm_sync(dapm);
>
> if (info->micd_reva) {
> diff --git a/drivers/input/misc/arizona-haptics.c b/drivers/input/misc/arizona-haptics.c
> index 7a04f54..ef2e281 100644
> --- a/drivers/input/misc/arizona-haptics.c
> +++ b/drivers/input/misc/arizona-haptics.c
> @@ -37,7 +37,6 @@ static void arizona_haptics_work(struct work_struct *work)
> struct arizona_haptics,
> work);
> struct arizona *arizona = haptics->arizona;
> - struct mutex *dapm_mutex = &arizona->dapm->card->dapm_mutex;
> int ret;
>
> if (!haptics->arizona->dapm) {
> @@ -67,13 +66,10 @@ static void arizona_haptics_work(struct work_struct *work)
> return;
> }
>
> - mutex_lock_nested(dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
> -
> ret = snd_soc_dapm_enable_pin(arizona->dapm, "HAPTICS");
> if (ret != 0) {
> dev_err(arizona->dev, "Failed to start HAPTICS: %d\n",
> ret);
> - mutex_unlock(dapm_mutex);
> return;
> }
>
Actually, this fixes also the double-lock in snd_soc_dapm_sync() call
in the line below the above. snd_soc_dapm_sync() itself takes
mutex_lock_nested().
> @@ -81,21 +77,14 @@ static void arizona_haptics_work(struct work_struct *work)
> if (ret != 0) {
> dev_err(arizona->dev, "Failed to sync DAPM: %d\n",
> ret);
> - mutex_unlock(dapm_mutex);
> return;
> }
> -
> - mutex_unlock(dapm_mutex);
> -
> } else {
> /* This disable sequence will be a noop if already enabled */
> - mutex_lock_nested(dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
> -
> ret = snd_soc_dapm_disable_pin(arizona->dapm, "HAPTICS");
> if (ret != 0) {
> dev_err(arizona->dev, "Failed to disable HAPTICS: %d\n",
> ret);
> - mutex_unlock(dapm_mutex);
> return;
> }
>
> @@ -103,12 +92,9 @@ static void arizona_haptics_work(struct work_struct *work)
> if (ret != 0) {
> dev_err(arizona->dev, "Failed to sync DAPM: %d\n",
> ret);
> - mutex_unlock(dapm_mutex);
> return;
> }
>
> - mutex_unlock(dapm_mutex);
> -
> ret = regmap_update_bits(arizona->regmap,
> ARIZONA_HAPTICS_CONTROL_1,
> ARIZONA_HAP_CTRL_MASK,
> @@ -155,16 +141,11 @@ static int arizona_haptics_play(struct input_dev *input, void *data,
> static void arizona_haptics_close(struct input_dev *input)
> {
> struct arizona_haptics *haptics = input_get_drvdata(input);
> - struct mutex *dapm_mutex = &haptics->arizona->dapm->card->dapm_mutex;
>
> cancel_work_sync(&haptics->work);
>
> - mutex_lock_nested(dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
> -
> if (haptics->arizona->dapm)
> snd_soc_dapm_disable_pin(haptics->arizona->dapm, "HAPTICS");
> -
> - mutex_unlock(dapm_mutex);
> }
>
> static int arizona_haptics_probe(struct platform_device *pdev)
> diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
> index dc8ff13..a44b560 100644
> --- a/sound/soc/soc-dapm.c
> +++ b/sound/soc/soc-dapm.c
> @@ -2325,6 +2325,8 @@ static int snd_soc_dapm_set_pin(struct snd_soc_dapm_context *dapm,
> {
> struct snd_soc_dapm_widget *w = dapm_find_widget(dapm, pin, true);
>
> + mutex_lock_nested(&dapm->card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
> +
> if (!w) {
> dev_err(dapm->dev, "ASoC: DAPM unknown pin %s\n", pin);
> return -EINVAL;
Missing unlock here.
> @@ -2337,6 +2339,8 @@ static int snd_soc_dapm_set_pin(struct snd_soc_dapm_context *dapm,
> if (status == 0)
> w->force = 0;
>
> + mutex_unlock(&dapm->card->dapm_mutex);
> +
> return 0;
> }
>
> @@ -3210,15 +3214,11 @@ int snd_soc_dapm_put_pin_switch(struct snd_kcontrol *kcontrol,
> struct snd_soc_card *card = snd_kcontrol_chip(kcontrol);
> const char *pin = (const char *)kcontrol->private_value;
>
> - mutex_lock_nested(&card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
> -
> if (ucontrol->value.integer.value[0])
> snd_soc_dapm_enable_pin(&card->dapm, pin);
> else
> snd_soc_dapm_disable_pin(&card->dapm, pin);
>
> - mutex_unlock(&card->dapm_mutex);
> -
> snd_soc_dapm_sync(&card->dapm);
> return 0;
> }
I guess you forgot patching snd_soc_dapm_force_enable_pin()?
It's now left unprotected after this patch.
Takashi
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