The patch number 8505 was added via Hans Verkuil <[EMAIL PROTECTED]>
to http://linuxtv.org/hg/v4l-dvb master development tree.
Kernel patches in this development tree may be modified to be backward
compatible with older kernels. Compatibility modifications will be
removed before inclusion into the mainstream Kernel
If anyone has any objections, please let us know by sending a message to:
[EMAIL PROTECTED]
------
From: Hans Verkuil <[EMAIL PROTECTED]>
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 <[EMAIL PROTECTED]>
---
linux/drivers/media/video/saa7134/saa7134-empress.c | 12 ++++--------
linux/drivers/media/video/saa7134/saa7134.h | 2 +-
2 files changed, 5 insertions(+), 9 deletions(-)
diff -r 5a829e462c87 -r 36481120006f
linux/drivers/media/video/saa7134/saa7134-empress.c
--- a/linux/drivers/media/video/saa7134/saa7134-empress.c Fri Jul 25
12:39:54 2008 +0200
+++ b/linux/drivers/media/video/saa7134/saa7134-empress.c Sat Jul 26
14:01:24 2008 +0200
@@ -89,14 +89,14 @@ static int ts_open(struct inode *inode,
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 *inod
{
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 *inod
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;
}
@@ -455,7 +451,7 @@ static void empress_signal_update(struct
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 -r 5a829e462c87 -r 36481120006f linux/drivers/media/video/saa7134/saa7134.h
--- a/linux/drivers/media/video/saa7134/saa7134.h Fri Jul 25 12:39:54
2008 +0200
+++ b/linux/drivers/media/video/saa7134/saa7134.h Sat Jul 26 14:01:24
2008 +0200
@@ -566,7 +566,7 @@ 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;
---
Patch is available at:
http://linuxtv.org/hg/v4l-dvb/rev/36481120006fffd8a170919022de4da6e2c4a1cb
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