From: Hans Verkuil Date: Sat, 26 Jul 2008 12:01:24 +0000 (-0300) Subject: V4L/DVB (8505): saa7134-empress.c: fix deadlock X-Git-Tag: v2.6.27-rc1~31^2~36 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=1052efe0fc69130d9d6a44bc9ceecd229221d9a1;p=linux-2.6-omap-h63xx.git V4L/DVB (8505): saa7134-empress.c: fix deadlock ts_release() locked a mutex that videobuf_stop() also tried to obtain. But ts_release() shouldn't hold that mutex at all. Make empress_users atomic as well to prevent possible race condition. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/video/saa7134/saa7134-empress.c b/drivers/media/video/saa7134/saa7134-empress.c index 8b3f9516778..2ecfbd1b41f 100644 --- a/drivers/media/video/saa7134/saa7134-empress.c +++ b/drivers/media/video/saa7134/saa7134-empress.c @@ -89,14 +89,14 @@ static int ts_open(struct inode *inode, struct file *file) err = -EBUSY; if (!mutex_trylock(&dev->empress_tsq.vb_lock)) goto done; - if (dev->empress_users) + if (atomic_read(&dev->empress_users)) goto done_up; /* Unmute audio */ saa_writeb(SAA7134_AUDIO_MUTE_CTRL, saa_readb(SAA7134_AUDIO_MUTE_CTRL) & ~(1 << 6)); - dev->empress_users++; + atomic_inc(&dev->empress_users); file->private_data = dev; err = 0; @@ -110,8 +110,6 @@ static int ts_release(struct inode *inode, struct file *file) { struct saa7134_dev *dev = file->private_data; - mutex_lock(&dev->empress_tsq.vb_lock); - videobuf_stop(&dev->empress_tsq); videobuf_mmap_free(&dev->empress_tsq); @@ -122,9 +120,7 @@ static int ts_release(struct inode *inode, struct file *file) saa_writeb(SAA7134_AUDIO_MUTE_CTRL, saa_readb(SAA7134_AUDIO_MUTE_CTRL) | (1 << 6)); - dev->empress_users--; - - mutex_unlock(&dev->empress_tsq.vb_lock); + atomic_dec(&dev->empress_users); return 0; } @@ -447,7 +443,7 @@ static void empress_signal_update(struct work_struct *work) ts_reset_encoder(dev); } else { dprintk("video signal acquired\n"); - if (dev->empress_users) + if (atomic_read(&dev->empress_users)) ts_init_encoder(dev); } } diff --git a/drivers/media/video/saa7134/saa7134.h b/drivers/media/video/saa7134/saa7134.h index ade4e19799e..ed20dd56379 100644 --- a/drivers/media/video/saa7134/saa7134.h +++ b/drivers/media/video/saa7134/saa7134.h @@ -561,7 +561,7 @@ struct saa7134_dev { /* SAA7134_MPEG_EMPRESS only */ struct video_device *empress_dev; struct videobuf_queue empress_tsq; - unsigned int empress_users; + atomic_t empress_users; struct work_struct empress_workqueue; int empress_started;