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ALSA: usb-audio: Use rwsem for disconnect protection 

Replace mutex with rwsem for codec->shutdown protection so that
concurrent accesses are allowed.

Also add the protection to snd_usb_autosuspend() and
snd_usb_autoresume(), too.

Reported-by: Matthieu CASTET <matthieu.castet@parrot.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2012-10-15 12:16:02 +02:00
parent 978520b75f
commit 34f3c89fda
4 changed files with 21 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
sound/usb/card.c
View File

@ -339,7 +339,7 @@ static int snd_usb_audio_create(struct usb_device *dev, int idx,
}
mutex_init(&chip->mutex);
mutex_init(&chip->shutdown_mutex);
init_rwsem(&chip->shutdown_rwsem);
chip->index = idx;
chip->dev = dev;
chip->card = card;
@ -560,7 +560,7 @@ static void snd_usb_audio_disconnect(struct usb_device *dev,
card = chip->card;
mutex_lock(&register_mutex);
mutex_lock(&chip->shutdown_mutex);
down_write(&chip->shutdown_rwsem);
chip->shutdown = 1;
chip->num_interfaces--;
if (chip->num_interfaces <= 0) {
@ -582,11 +582,11 @@ static void snd_usb_audio_disconnect(struct usb_device *dev,
snd_usb_mixer_disconnect(p);
}
usb_chip[chip->index] = NULL;
mutex_unlock(&chip->shutdown_mutex);
up_write(&chip->shutdown_rwsem);
mutex_unlock(&register_mutex);
snd_card_free_when_closed(card);
} else {
mutex_unlock(&chip->shutdown_mutex);
up_write(&chip->shutdown_rwsem);
mutex_unlock(&register_mutex);
}
}
@ -618,16 +618,20 @@ int snd_usb_autoresume(struct snd_usb_audio *chip)
{
int err = -ENODEV;
down_read(&chip->shutdown_rwsem);
if (!chip->shutdown && !chip->probing)
err = usb_autopm_get_interface(chip->pm_intf);
up_read(&chip->shutdown_rwsem);
return err;
}
void snd_usb_autosuspend(struct snd_usb_audio *chip)
{
down_read(&chip->shutdown_rwsem);
if (!chip->shutdown && !chip->probing)
usb_autopm_put_interface(chip->pm_intf);
up_read(&chip->shutdown_rwsem);
}
static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)

12
sound/usb/mixer.c
View File

@ -292,7 +292,7 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request, int v
err = snd_usb_autoresume(cval->mixer->chip);
if (err < 0)
return -EIO;
mutex_lock(&chip->shutdown_mutex);
down_read(&chip->shutdown_rwsem);
while (timeout-- > 0) {
if (chip->shutdown)
break;
@ -310,7 +310,7 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request, int v
err = -EINVAL;
out:
mutex_unlock(&chip->shutdown_mutex);
up_read(&chip->shutdown_rwsem);
snd_usb_autosuspend(cval->mixer->chip);
return err;
}
@ -337,7 +337,7 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
if (ret)
goto error;
mutex_lock(&chip->shutdown_mutex);
down_read(&chip->shutdown_rwsem);
if (chip->shutdown)
ret = -ENODEV;
else {
@ -346,7 +346,7 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
validx, idx, buf, size);
}
mutex_unlock(&chip->shutdown_mutex);
up_read(&chip->shutdown_rwsem);
snd_usb_autosuspend(chip);
if (ret < 0) {
@ -453,7 +453,7 @@ int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
err = snd_usb_autoresume(chip);
if (err < 0)
return -EIO;
mutex_lock(&chip->shutdown_mutex);
down_read(&chip->shutdown_rwsem);
while (timeout-- > 0) {
if (chip->shutdown)
break;
@ -471,7 +471,7 @@ int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
err = -EINVAL;
out:
mutex_unlock(&chip->shutdown_mutex);
up_read(&chip->shutdown_rwsem);
snd_usb_autosuspend(chip);
return err;
}

12
sound/usb/pcm.c
View File

@ -503,12 +503,12 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
return -EINVAL;
}
mutex_lock(&subs->stream->chip->shutdown_mutex);
down_read(&subs->stream->chip->shutdown_rwsem);
if (subs->stream->chip->shutdown)
ret = -ENODEV;
else
ret = set_format(subs, fmt);
mutex_unlock(&subs->stream->chip->shutdown_mutex);
up_read(&subs->stream->chip->shutdown_rwsem);
if (ret < 0)
return ret;
@ -531,12 +531,12 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)
subs->cur_audiofmt = NULL;
subs->cur_rate = 0;
subs->period_bytes = 0;
mutex_lock(&subs->stream->chip->shutdown_mutex);
down_read(&subs->stream->chip->shutdown_rwsem);
if (!subs->stream->chip->shutdown) {
stop_endpoints(subs, 0, 1, 1);
deactivate_endpoints(subs);
}
mutex_unlock(&subs->stream->chip->shutdown_mutex);
up_read(&subs->stream->chip->shutdown_rwsem);
return snd_pcm_lib_free_vmalloc_buffer(substream);
}
@ -558,7 +558,7 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
return -ENXIO;
}
mutex_lock(&subs->stream->chip->shutdown_mutex);
down_read(&subs->stream->chip->shutdown_rwsem);
if (subs->stream->chip->shutdown) {
ret = -ENODEV;
goto unlock;
@ -608,7 +608,7 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
ret = start_endpoints(subs, 1);
unlock:
mutex_unlock(&subs->stream->chip->shutdown_mutex);
up_read(&subs->stream->chip->shutdown_rwsem);
return ret;
}

2
sound/usb/usbaudio.h
View File

@ -37,7 +37,7 @@ struct snd_usb_audio {
struct usb_interface *pm_intf;
u32 usb_id;
struct mutex mutex;
struct mutex shutdown_mutex;
struct rw_semaphore shutdown_rwsem;
unsigned int shutdown:1;
unsigned int probing:1;
unsigned int autosuspended:1;