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[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: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab 2010-10-09 15:53:58 -03:00
parent 643800d5c8
commit 39a96b4cf5
2 changed files with 43 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
drivers/media/video/em28xx/em28xx-audio.c
View File

@ -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);

19
drivers/media/video/em28xx/em28xx.h
View File

@ -25,12 +25,13 @@
#ifndef _EM28XX_H
#define _EM28XX_H
#include <linux/videodev2.h>
#include <media/videobuf-vmalloc.h>
#include <media/v4l2-device.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 <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;