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Commit 39a96b4c authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
Browse files

[media] em28xx-audio: fix some locking issues 



Those locking issues affect tvtime, causing a kernel oops/panic, due to
a race condition.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 643800d5

drivers/media/video/em28xx/em28xx-audio.c

+34 −41
Original line number Diff line number Diff line
@@ -102,6 +102,9 @@ static void em28xx_audio_isocirq(struct urb *urb) 
		break;

	}



	if (atomic_read(&dev->stream_started) == 0)

		return;



	if (dev->adev.capture_pcm_substream) {

		substream = dev->adev.capture_pcm_substream;

		runtime = substream->runtime;
@@ -217,31 +220,6 @@ static int em28xx_init_audio_isoc(struct em28xx *dev) 
	return 0;

}



static int em28xx_cmd(struct em28xx *dev, int cmd, int arg)

{

	dprintk("%s transfer\n", (dev->adev.capture_stream == STREAM_ON) ?

				 "stop" : "start");



	switch (cmd) {

	case EM28XX_CAPTURE_STREAM_EN:

		if (dev->adev.capture_stream == STREAM_OFF &&

		    arg == EM28XX_START_AUDIO) {

			dev->adev.capture_stream = STREAM_ON;

			em28xx_init_audio_isoc(dev);

		} else if (dev->adev.capture_stream == STREAM_ON &&

			   arg == EM28XX_STOP_AUDIO) {

			dev->adev.capture_stream = STREAM_OFF;

			em28xx_deinit_isoc_audio(dev);

		} else {

			em28xx_errdev("An underrun very likely occurred. "

					"Ignoring it.\n");

		}

		return 0;

	default:

		return -EINVAL;

	}

}



static int snd_pcm_alloc_vmalloc_buffer(struct snd_pcm_substream *subs,

					size_t size)

{
@@ -303,7 +281,6 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream) 
	dev->mute = 0;

	mutex_lock(&dev->lock);

	ret = em28xx_audio_analog_set(dev);

	mutex_unlock(&dev->lock);

	if (ret < 0)

		goto err;
@@ -311,11 +288,10 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream) 
	if (dev->alt == 0 && dev->adev.users == 0) {

		int errCode;

		dev->alt = 7;

		errCode = usb_set_interface(dev->udev, 0, 7);

		dprintk("changing alternate number to 7\n");

		errCode = usb_set_interface(dev->udev, 0, 7);

	}



	mutex_lock(&dev->lock);

	dev->adev.users++;

	mutex_unlock(&dev->lock);
@@ -325,6 +301,8 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream) 


	return 0;

err:

	mutex_unlock(&dev->lock);



	em28xx_err("Error while configuring em28xx mixer\n");

	return ret;

}
@@ -338,6 +316,11 @@ static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream) 
	dev->mute = 1;

	mutex_lock(&dev->lock);

	dev->adev.users--;

	if (atomic_read(&dev->stream_started) > 0) {

		atomic_set(&dev->stream_started, 0);

		schedule_work(&dev->wq_trigger);

	}



	em28xx_audio_analog_set(dev);

	if (substream->runtime->dma_area) {

		dprintk("freeing\n");
@@ -375,8 +358,10 @@ static int snd_em28xx_hw_capture_free(struct snd_pcm_substream *substream) 


	dprintk("Stop capture, if needed\n");



	if (dev->adev.capture_stream == STREAM_ON)

		em28xx_cmd(dev, EM28XX_CAPTURE_STREAM_EN, EM28XX_STOP_AUDIO);

	if (atomic_read(&dev->stream_started) > 0) {

		atomic_set(&dev->stream_started, 0);

		schedule_work(&dev->wq_trigger);

	}



	return 0;

}
@@ -391,31 +376,37 @@ static int snd_em28xx_prepare(struct snd_pcm_substream *substream) 
	return 0;

}



static void audio_trigger(struct work_struct *work)

{

	struct em28xx *dev = container_of(work, struct em28xx, wq_trigger);



	if (atomic_read(&dev->stream_started)) {

		dprintk("starting capture");

		em28xx_init_audio_isoc(dev);

	} else {

		dprintk("stopping capture");

		em28xx_deinit_isoc_audio(dev);

	}

}



static int snd_em28xx_capture_trigger(struct snd_pcm_substream *substream,

				      int cmd)

{

	struct em28xx *dev = snd_pcm_substream_chip(substream);

	int retval;



	dprintk("Should %s capture\n", (cmd == SNDRV_PCM_TRIGGER_START) ?

				       "start" : "stop");



	spin_lock(&dev->adev.slock);

	switch (cmd) {

	case SNDRV_PCM_TRIGGER_START:

		em28xx_cmd(dev, EM28XX_CAPTURE_STREAM_EN, EM28XX_START_AUDIO);

		retval = 0;

		atomic_set(&dev->stream_started, 1);

		break;

	case SNDRV_PCM_TRIGGER_STOP:

		em28xx_cmd(dev, EM28XX_CAPTURE_STREAM_EN, EM28XX_STOP_AUDIO);

		retval = 0;

		atomic_set(&dev->stream_started, 1);

		break;

	default:

		retval = -EINVAL;

	}



	spin_unlock(&dev->adev.slock);

	return retval;

	schedule_work(&dev->wq_trigger);

	return 0;

}



static snd_pcm_uframes_t snd_em28xx_capture_pointer(struct snd_pcm_substream
@@ -495,6 +486,8 @@ static int em28xx_audio_init(struct em28xx *dev) 
	strcpy(card->shortname, "Em28xx Audio");

	strcpy(card->longname, "Empia Em28xx Audio");



	INIT_WORK(&dev->wq_trigger, audio_trigger);



	err = snd_card_register(card);

	if (err < 0) {

		snd_card_free(card);

drivers/media/video/em28xx/em28xx.h

+8 −9
Original line number Diff line number Diff line
@@ -25,12 +25,13 @@ 
#ifndef _EM28XX_H

#define _EM28XX_H



#include <linux/workqueue.h>

#include <linux/i2c.h>

#include <linux/mutex.h>

#include <linux/videodev2.h>



#include <media/videobuf-vmalloc.h>

#include <media/v4l2-device.h>



#include <linux/i2c.h>

#include <linux/mutex.h>

#include <media/ir-kbd-i2c.h>

#include <media/ir-core.h>

#if defined(CONFIG_VIDEO_EM28XX_DVB) || defined(CONFIG_VIDEO_EM28XX_DVB_MODULE)
@@ -184,11 +185,6 @@ enum em28xx_mode { 
	EM28XX_DIGITAL_MODE,

};



enum em28xx_stream_state {

	STREAM_OFF,

	STREAM_INTERRUPT,

	STREAM_ON,

};



struct em28xx;
@@ -463,7 +459,6 @@ struct em28xx_audio { 
	struct snd_card            *sndcard;



	int users;

	enum em28xx_stream_state capture_stream;

	spinlock_t slock;

};
@@ -505,6 +500,10 @@ struct em28xx { 
	unsigned int has_audio_class:1;

	unsigned int has_alsa_audio:1;



	/* Controls audio streaming */

	struct work_struct wq_trigger;              /* Trigger to start/stop audio for alsa module */

	 atomic_t       stream_started;      /* stream should be running if true */



	struct em28xx_fmt *format;



	struct em28xx_IR *ir;