Re: [PATCH repost2 1/2] V4L: hdpvr, fix lock imbalances

From: Douglas Schilling Landgraf
Date: Thu Jul 30 2009 - 19:47:37 EST


Hello Jiri,

On Thu, 30 Jul 2009 23:49:48 +0200
Jiri Slaby <jirislaby@xxxxxxxxx> wrote:

> Hrm, nobody picked these up, twice. Maybe this time :)?
> --

Thanks for this email. Both patches are applied to devel tree.

Cheers,
Douglas

> There are many lock imbalances in this driver. Fix all found.
>
> Signed-off-by: Jiri Slaby <jirislaby@xxxxxxxxx>
> ---
> drivers/media/video/hdpvr/hdpvr-core.c | 12 ++++++------
> drivers/media/video/hdpvr/hdpvr-video.c | 6 ++++--
> 2 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/media/video/hdpvr/hdpvr-core.c
> b/drivers/media/video/hdpvr/hdpvr-core.c index 188bd5a..1c9bc94 100644
> --- a/drivers/media/video/hdpvr/hdpvr-core.c
> +++ b/drivers/media/video/hdpvr/hdpvr-core.c
> @@ -126,7 +126,7 @@ static int device_authorization(struct
> hdpvr_device *dev) char *print_buf = kzalloc(5*buf_size+1,
> GFP_KERNEL); if (!print_buf) {
> v4l2_err(&dev->v4l2_dev, "Out of memory\n");
> - goto error;
> + return retval;
> }
> #endif
>
> @@ -140,7 +140,7 @@ static int device_authorization(struct
> hdpvr_device *dev) if (ret != 46) {
> v4l2_err(&dev->v4l2_dev,
> "unexpected answer of status request, len
> %d\n", ret);
> - goto error;
> + goto unlock;
> }
> #ifdef HDPVR_DEBUG
> else {
> @@ -163,7 +163,7 @@ static int device_authorization(struct
> hdpvr_device *dev) v4l2_err(&dev->v4l2_dev, "unknown firmware version
> 0x%x\n", dev->usbc_buf[1]);
> ret = -EINVAL;
> - goto error;
> + goto unlock;
> }
>
> response = dev->usbc_buf+38;
> @@ -188,10 +188,10 @@ static int device_authorization(struct
> hdpvr_device *dev) 10000);
> v4l2_dbg(MSG_INFO, hdpvr_debug, &dev->v4l2_dev,
> "magic request returned %d\n", ret);
> - mutex_unlock(&dev->usbc_mutex);
>
> retval = ret != 8;
> -error:
> +unlock:
> + mutex_unlock(&dev->usbc_mutex);
> return retval;
> }
>
> @@ -350,6 +350,7 @@ static int hdpvr_probe(struct usb_interface
> *interface,
> mutex_lock(&dev->io_mutex);
> if (hdpvr_alloc_buffers(dev, NUM_BUFFERS)) {
> + mutex_unlock(&dev->io_mutex);
> v4l2_err(&dev->v4l2_dev,
> "allocating transfer buffers failed\n");
> goto error;
> @@ -381,7 +382,6 @@ static int hdpvr_probe(struct usb_interface
> *interface,
> error:
> if (dev) {
> - mutex_unlock(&dev->io_mutex);
> /* this frees allocated memory */
> hdpvr_delete(dev);
> }
> diff --git a/drivers/media/video/hdpvr/hdpvr-video.c
> b/drivers/media/video/hdpvr/hdpvr-video.c index ccd47f5..5937de2
> 100644 --- a/drivers/media/video/hdpvr/hdpvr-video.c
> +++ b/drivers/media/video/hdpvr/hdpvr-video.c
> @@ -375,6 +375,7 @@ static int hdpvr_open(struct file *file)
> * in resumption */
> mutex_lock(&dev->io_mutex);
> dev->open_count++;
> + mutex_unlock(&dev->io_mutex);
>
> fh->dev = dev;
>
> @@ -383,7 +384,6 @@ static int hdpvr_open(struct file *file)
>
> retval = 0;
> err:
> - mutex_unlock(&dev->io_mutex);
> return retval;
> }
>
> @@ -519,8 +519,10 @@ static unsigned int hdpvr_poll(struct file
> *filp, poll_table *wait)
> mutex_lock(&dev->io_mutex);
>
> - if (video_is_unregistered(dev->video_dev))
> + if (video_is_unregistered(dev->video_dev)) {
> + mutex_unlock(&dev->io_mutex);
> return -EIO;
> + }
>
> if (dev->status == STATUS_IDLE) {
> if (hdpvr_start_streaming(dev)) {

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