diff mbox

[v4,15/22,media] em28xx: Fix em28xx deplock

Message ID 1388832951-11195-16-git-send-email-m.chehab@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mauro Carvalho Chehab Jan. 4, 2014, 10:55 a.m. UTC
When em28xx extensions are loaded/removed, there are two locks:

a single static em28xx_devlist_mutex that registers each extension
and the struct em28xx dev->lock.

When extensions are registered, em28xx_devlist_mutex is taken first,
and then dev->lock.

Be sure that, when extensions are being removed, the same order
will be used.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---
 drivers/media/usb/em28xx/em28xx-cards.c | 5 +++--
 drivers/media/usb/em28xx/em28xx-core.c  | 2 ++
 2 files changed, 5 insertions(+), 2 deletions(-)

Comments

Frank Schäfer Jan. 5, 2014, 11:38 a.m. UTC | #1
Am 04.01.2014 11:55, schrieb Mauro Carvalho Chehab:
> When em28xx extensions are loaded/removed, there are two locks:
>
> a single static em28xx_devlist_mutex that registers each extension
> and the struct em28xx dev->lock.
>
> When extensions are registered, em28xx_devlist_mutex is taken first,
> and then dev->lock.
>
> Be sure that, when extensions are being removed, the same order
> will be used.
>
> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
> ---
>  drivers/media/usb/em28xx/em28xx-cards.c | 5 +++--
>  drivers/media/usb/em28xx/em28xx-core.c  | 2 ++
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
> index 4fe742429f2c..36aec50e5c3b 100644
> --- a/drivers/media/usb/em28xx/em28xx-cards.c
> +++ b/drivers/media/usb/em28xx/em28xx-cards.c
> @@ -3334,9 +3334,7 @@ static void em28xx_usb_disconnect(struct usb_interface *interface)
>  	dev->disconnected = 1;
>  
>  	if (dev->is_audio_only) {
> -		mutex_lock(&dev->lock);
>  		em28xx_close_extension(dev);
> -		mutex_unlock(&dev->lock);
>  		return;
>  	}
>  
> @@ -3355,10 +3353,13 @@ static void em28xx_usb_disconnect(struct usb_interface *interface)
>  		em28xx_uninit_usb_xfer(dev, EM28XX_ANALOG_MODE);
>  		em28xx_uninit_usb_xfer(dev, EM28XX_DIGITAL_MODE);
>  	}
> +	mutex_unlock(&dev->lock);
>  
>  	em28xx_close_extension(dev);
> +
>  	/* NOTE: must be called BEFORE the resources are released */
>  
> +	mutex_lock(&dev->lock);
>  	if (!dev->users)
>  		em28xx_release_resources(dev);
>  
> diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
> index 2ad84ff1fc4f..97cc83c3c287 100644
> --- a/drivers/media/usb/em28xx/em28xx-core.c
> +++ b/drivers/media/usb/em28xx/em28xx-core.c
> @@ -1097,10 +1097,12 @@ void em28xx_close_extension(struct em28xx *dev)
>  	const struct em28xx_ops *ops = NULL;
>  
>  	mutex_lock(&em28xx_devlist_mutex);
> +	mutex_lock(&dev->lock);
>  	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
>  		if (ops->fini)
>  			ops->fini(dev);
>  	}
> +	mutex_unlock(&dev->lock);
>  	list_del(&dev->devlist);
>  	mutex_unlock(&em28xx_devlist_mutex);
>  }

Reviewed-by: Frank Schäfer <fschaefer.oss@googlemail.com>

Thank you for fixing this issue.

I will review the remaining patches this evening.

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index 4fe742429f2c..36aec50e5c3b 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -3334,9 +3334,7 @@  static void em28xx_usb_disconnect(struct usb_interface *interface)
 	dev->disconnected = 1;
 
 	if (dev->is_audio_only) {
-		mutex_lock(&dev->lock);
 		em28xx_close_extension(dev);
-		mutex_unlock(&dev->lock);
 		return;
 	}
 
@@ -3355,10 +3353,13 @@  static void em28xx_usb_disconnect(struct usb_interface *interface)
 		em28xx_uninit_usb_xfer(dev, EM28XX_ANALOG_MODE);
 		em28xx_uninit_usb_xfer(dev, EM28XX_DIGITAL_MODE);
 	}
+	mutex_unlock(&dev->lock);
 
 	em28xx_close_extension(dev);
+
 	/* NOTE: must be called BEFORE the resources are released */
 
+	mutex_lock(&dev->lock);
 	if (!dev->users)
 		em28xx_release_resources(dev);
 
diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index 2ad84ff1fc4f..97cc83c3c287 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -1097,10 +1097,12 @@  void em28xx_close_extension(struct em28xx *dev)
 	const struct em28xx_ops *ops = NULL;
 
 	mutex_lock(&em28xx_devlist_mutex);
+	mutex_lock(&dev->lock);
 	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
 		if (ops->fini)
 			ops->fini(dev);
 	}
+	mutex_unlock(&dev->lock);
 	list_del(&dev->devlist);
 	mutex_unlock(&em28xx_devlist_mutex);
 }