* Re: [PATCH] pwc: better usb disconnect handling
2011-06-06 17:43 ` [PATCH] pwc: better usb disconnect handling Hans de Goede
@ 2011-06-21 16:32 ` Mauro Carvalho Chehab
0 siblings, 0 replies; 2+ messages in thread
From: Mauro Carvalho Chehab @ 2011-06-21 16:32 UTC (permalink / raw)
To: Hans de Goede; +Cc: Linux Media Mailing List
Em 06-06-2011 14:43, Hans de Goede escreveu:
> Unplugging a pwc cam while an app has the /dev/video# node open leads
> to an oops in pwc_video_close when the app closes the node, because
> the disconnect handler has free-ed the pdev struct pwc_video_close
> tries to use. Instead of adding some sort of bandaid for this.
> fix it properly using the v4l2 core's new(ish) behavior of keeping the
> v4l2_dev structure around until both unregister has been called, and
> all file handles referring to it have been closed:
>
> Embed the v4l2_dev structure in the pdev structure and define a v4l2 dev
> release callback releasing the pdev structure (and thus also the embedded
> v4l2 dev structure.
Hans,
I'm adding this patch into my fixes tree. After applying upstream, it
will be sent automatically to the stable team. Next time, instead of
c/c them on an email, all you need to do is to add an extra tag after your
SOB, like:
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: stable@kernel.org
Cheers,
Mauro
> ---
> drivers/media/video/pwc/pwc-ctrl.c | 2 +-
> drivers/media/video/pwc/pwc-if.c | 152 +++++++++++-------------------------
> drivers/media/video/pwc/pwc.h | 4 +-
> 3 files changed, 50 insertions(+), 108 deletions(-)
>
> diff --git a/drivers/media/video/pwc/pwc-ctrl.c b/drivers/media/video/pwc/pwc-ctrl.c
> index 1593f8d..760b4de 100644
> --- a/drivers/media/video/pwc/pwc-ctrl.c
> +++ b/drivers/media/video/pwc/pwc-ctrl.c
> @@ -1414,7 +1414,7 @@ long pwc_ioctl(struct pwc_device *pdev, unsigned int cmd, void *arg)
> {
> ARG_DEF(struct pwc_probe, probe)
>
> - strcpy(ARGR(probe).name, pdev->vdev->name);
> + strcpy(ARGR(probe).name, pdev->vdev.name);
> ARGR(probe).type = pdev->type;
> ARG_OUT(probe)
> break;
> diff --git a/drivers/media/video/pwc/pwc-if.c b/drivers/media/video/pwc/pwc-if.c
> index b81024c..592f966 100644
> --- a/drivers/media/video/pwc/pwc-if.c
> +++ b/drivers/media/video/pwc/pwc-if.c
> @@ -40,7 +40,7 @@
> Oh yes, convention: to disctinguish between all the various pointers to
> device-structures, I use these names for the pointer variables:
> udev: struct usb_device *
> - vdev: struct video_device *
> + vdev: struct video_device (member of pwc_dev)
> pdev: struct pwc_devive *
> */
>
> @@ -152,6 +152,7 @@ static ssize_t pwc_video_read(struct file *file, char __user *buf,
> size_t count, loff_t *ppos);
> static unsigned int pwc_video_poll(struct file *file, poll_table *wait);
> static int pwc_video_mmap(struct file *file, struct vm_area_struct *vma);
> +static void pwc_video_release(struct video_device *vfd);
>
> static const struct v4l2_file_operations pwc_fops = {
> .owner = THIS_MODULE,
> @@ -164,42 +165,12 @@ static const struct v4l2_file_operations pwc_fops = {
> };
> static struct video_device pwc_template = {
> .name = "Philips Webcam", /* Filled in later */
> - .release = video_device_release,
> + .release = pwc_video_release,
> .fops = &pwc_fops,
> + .ioctl_ops = &pwc_ioctl_ops,
> };
>
> /***************************************************************************/
> -
> -/* Okay, this is some magic that I worked out and the reasoning behind it...
> -
> - The biggest problem with any USB device is of course: "what to do
> - when the user unplugs the device while it is in use by an application?"
> - We have several options:
> - 1) Curse them with the 7 plagues when they do (requires divine intervention)
> - 2) Tell them not to (won't work: they'll do it anyway)
> - 3) Oops the kernel (this will have a negative effect on a user's uptime)
> - 4) Do something sensible.
> -
> - Of course, we go for option 4.
> -
> - It happens that this device will be linked to two times, once from
> - usb_device and once from the video_device in their respective 'private'
> - pointers. This is done when the device is probed() and all initialization
> - succeeded. The pwc_device struct links back to both structures.
> -
> - When a device is unplugged while in use it will be removed from the
> - list of known USB devices; I also de-register it as a V4L device, but
> - unfortunately I can't free the memory since the struct is still in use
> - by the file descriptor. This free-ing is then deferend until the first
> - opportunity. Crude, but it works.
> -
> - A small 'advantage' is that if a user unplugs the cam and plugs it back
> - in, it should get assigned the same video device minor, but unfortunately
> - it's non-trivial to re-link the cam back to the video device... (that
> - would surely be magic! :))
> -*/
> -
> -/***************************************************************************/
> /* Private functions */
>
> /* Here we want the physical address of the memory.
> @@ -1017,16 +988,15 @@ static ssize_t show_snapshot_button_status(struct device *class_dev,
> static DEVICE_ATTR(button, S_IRUGO | S_IWUSR, show_snapshot_button_status,
> NULL);
>
> -static int pwc_create_sysfs_files(struct video_device *vdev)
> +static int pwc_create_sysfs_files(struct pwc_device *pdev)
> {
> - struct pwc_device *pdev = video_get_drvdata(vdev);
> int rc;
>
> - rc = device_create_file(&vdev->dev, &dev_attr_button);
> + rc = device_create_file(&pdev->vdev.dev, &dev_attr_button);
> if (rc)
> goto err;
> if (pdev->features & FEATURE_MOTOR_PANTILT) {
> - rc = device_create_file(&vdev->dev, &dev_attr_pan_tilt);
> + rc = device_create_file(&pdev->vdev.dev, &dev_attr_pan_tilt);
> if (rc)
> goto err_button;
> }
> @@ -1034,19 +1004,17 @@ static int pwc_create_sysfs_files(struct video_device *vdev)
> return 0;
>
> err_button:
> - device_remove_file(&vdev->dev, &dev_attr_button);
> + device_remove_file(&pdev->vdev.dev, &dev_attr_button);
> err:
> PWC_ERROR("Could not create sysfs files.\n");
> return rc;
> }
>
> -static void pwc_remove_sysfs_files(struct video_device *vdev)
> +static void pwc_remove_sysfs_files(struct pwc_device *pdev)
> {
> - struct pwc_device *pdev = video_get_drvdata(vdev);
> -
> if (pdev->features & FEATURE_MOTOR_PANTILT)
> - device_remove_file(&vdev->dev, &dev_attr_pan_tilt);
> - device_remove_file(&vdev->dev, &dev_attr_button);
> + device_remove_file(&pdev->vdev.dev, &dev_attr_pan_tilt);
> + device_remove_file(&pdev->vdev.dev, &dev_attr_button);
> }
>
> #ifdef CONFIG_USB_PWC_DEBUG
> @@ -1107,7 +1075,7 @@ static int pwc_video_open(struct file *file)
> if (ret >= 0)
> {
> PWC_DEBUG_OPEN("This %s camera is equipped with a %s (%d).\n",
> - pdev->vdev->name,
> + pdev->vdev.name,
> pwc_sensor_type_to_string(i), i);
> }
> }
> @@ -1181,16 +1149,15 @@ static int pwc_video_open(struct file *file)
> return 0;
> }
>
> -
> -static void pwc_cleanup(struct pwc_device *pdev)
> +static void pwc_video_release(struct video_device *vfd)
> {
> - pwc_remove_sysfs_files(pdev->vdev);
> - video_unregister_device(pdev->vdev);
> + struct pwc_device *pdev = container_of(vfd, struct pwc_device, vdev);
> + int hint;
>
> -#ifdef CONFIG_USB_PWC_INPUT_EVDEV
> - if (pdev->button_dev)
> - input_unregister_device(pdev->button_dev);
> -#endif
> + /* search device_hint[] table if we occupy a slot, by any chance */
> + for (hint = 0; hint < MAX_DEV_HINTS; hint++)
> + if (device_hint[hint].pdev == pdev)
> + device_hint[hint].pdev = NULL;
>
> kfree(pdev);
> }
> @@ -1200,7 +1167,7 @@ static int pwc_video_close(struct file *file)
> {
> struct video_device *vdev = file->private_data;
> struct pwc_device *pdev;
> - int i, hint;
> + int i;
>
> PWC_DEBUG_OPEN(">> video_close called(vdev = 0x%p).\n", vdev);
>
> @@ -1235,12 +1202,6 @@ static int pwc_video_close(struct file *file)
> }
> pdev->vopen--;
> PWC_DEBUG_OPEN("<< video_close() vopen=%d\n", pdev->vopen);
> - } else {
> - pwc_cleanup(pdev);
> - /* search device_hint[] table if we occupy a slot, by any chance */
> - for (hint = 0; hint < MAX_DEV_HINTS; hint++)
> - if (device_hint[hint].pdev == pdev)
> - device_hint[hint].pdev = NULL;
> }
>
> return 0;
> @@ -1716,19 +1677,12 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
> init_waitqueue_head(&pdev->frameq);
> pdev->vcompression = pwc_preferred_compression;
>
> - /* Allocate video_device structure */
> - pdev->vdev = video_device_alloc();
> - if (!pdev->vdev) {
> - PWC_ERROR("Err, cannot allocate video_device struture. Failing probe.");
> - rc = -ENOMEM;
> - goto err_free_mem;
> - }
> - memcpy(pdev->vdev, &pwc_template, sizeof(pwc_template));
> - pdev->vdev->parent = &intf->dev;
> - pdev->vdev->lock = &pdev->modlock;
> - pdev->vdev->ioctl_ops = &pwc_ioctl_ops;
> - strcpy(pdev->vdev->name, name);
> - video_set_drvdata(pdev->vdev, pdev);
> + /* Init video_device structure */
> + memcpy(&pdev->vdev, &pwc_template, sizeof(pwc_template));
> + pdev->vdev.parent = &intf->dev;
> + pdev->vdev.lock = &pdev->modlock;
> + strcpy(pdev->vdev.name, name);
> + video_set_drvdata(&pdev->vdev, pdev);
>
> pdev->release = le16_to_cpu(udev->descriptor.bcdDevice);
> PWC_DEBUG_PROBE("Release: %04x\n", pdev->release);
> @@ -1747,8 +1701,6 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
> }
> }
>
> - pdev->vdev->release = video_device_release;
> -
> /* occupy slot */
> if (hint < MAX_DEV_HINTS)
> device_hint[hint].pdev = pdev;
> @@ -1760,16 +1712,16 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
> pwc_set_leds(pdev, 0, 0);
> pwc_camera_power(pdev, 0);
>
> - rc = video_register_device(pdev->vdev, VFL_TYPE_GRABBER, video_nr);
> + rc = video_register_device(&pdev->vdev, VFL_TYPE_GRABBER, video_nr);
> if (rc < 0) {
> PWC_ERROR("Failed to register as video device (%d).\n", rc);
> - goto err_video_release;
> + goto err_free_mem;
> }
> - rc = pwc_create_sysfs_files(pdev->vdev);
> + rc = pwc_create_sysfs_files(pdev);
> if (rc)
> goto err_video_unreg;
>
> - PWC_INFO("Registered as %s.\n", video_device_node_name(pdev->vdev));
> + PWC_INFO("Registered as %s.\n", video_device_node_name(&pdev->vdev));
>
> #ifdef CONFIG_USB_PWC_INPUT_EVDEV
> /* register webcam snapshot button input device */
> @@ -1777,7 +1729,7 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
> if (!pdev->button_dev) {
> PWC_ERROR("Err, insufficient memory for webcam snapshot button device.");
> rc = -ENOMEM;
> - pwc_remove_sysfs_files(pdev->vdev);
> + pwc_remove_sysfs_files(pdev);
> goto err_video_unreg;
> }
>
> @@ -1795,7 +1747,7 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
> if (rc) {
> input_free_device(pdev->button_dev);
> pdev->button_dev = NULL;
> - pwc_remove_sysfs_files(pdev->vdev);
> + pwc_remove_sysfs_files(pdev);
> goto err_video_unreg;
> }
> #endif
> @@ -1805,10 +1757,7 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
> err_video_unreg:
> if (hint < MAX_DEV_HINTS)
> device_hint[hint].pdev = NULL;
> - video_unregister_device(pdev->vdev);
> - pdev->vdev = NULL; /* So we don't try to release it below */
> -err_video_release:
> - video_device_release(pdev->vdev);
> + video_unregister_device(&pdev->vdev);
> err_free_mem:
> kfree(pdev);
> return rc;
> @@ -1817,10 +1766,8 @@ err_free_mem:
> /* The user yanked out the cable... */
> static void usb_pwc_disconnect(struct usb_interface *intf)
> {
> - struct pwc_device *pdev;
> - int hint;
> + struct pwc_device *pdev = usb_get_intfdata(intf);
>
> - pdev = usb_get_intfdata (intf);
> mutex_lock(&pdev->modlock);
> usb_set_intfdata (intf, NULL);
> if (pdev == NULL) {
> @@ -1837,30 +1784,25 @@ static void usb_pwc_disconnect(struct usb_interface *intf)
> }
>
> /* We got unplugged; this is signalled by an EPIPE error code */
> - if (pdev->vopen) {
> - PWC_INFO("Disconnected while webcam is in use!\n");
> - pdev->error_status = EPIPE;
> - }
> + pdev->error_status = EPIPE;
> + pdev->unplugged = 1;
>
> /* Alert waiting processes */
> wake_up_interruptible(&pdev->frameq);
> - /* Wait until device is closed */
> - if (pdev->vopen) {
> - pdev->unplugged = 1;
> - pwc_iso_stop(pdev);
> - } else {
> - /* Device is closed, so we can safely unregister it */
> - PWC_DEBUG_PROBE("Unregistering video device in disconnect().\n");
>
> -disconnect_out:
> - /* search device_hint[] table if we occupy a slot, by any chance */
> - for (hint = 0; hint < MAX_DEV_HINTS; hint++)
> - if (device_hint[hint].pdev == pdev)
> - device_hint[hint].pdev = NULL;
> - }
> + /* No need to keep the urbs around after disconnection */
> + pwc_isoc_cleanup(pdev);
>
> +disconnect_out:
> mutex_unlock(&pdev->modlock);
> - pwc_cleanup(pdev);
> +
> + pwc_remove_sysfs_files(pdev);
> + video_unregister_device(&pdev->vdev);
> +
> +#ifdef CONFIG_USB_PWC_INPUT_EVDEV
> + if (pdev->button_dev)
> + input_unregister_device(pdev->button_dev);
> +#endif
> }
>
>
> diff --git a/drivers/media/video/pwc/pwc.h b/drivers/media/video/pwc/pwc.h
> index e947766..083f8b1 100644
> --- a/drivers/media/video/pwc/pwc.h
> +++ b/drivers/media/video/pwc/pwc.h
> @@ -162,9 +162,9 @@ struct pwc_imgbuf
>
> struct pwc_device
> {
> - struct video_device *vdev;
> + struct video_device vdev;
>
> - /* Pointer to our usb_device */
> + /* Pointer to our usb_device, may be NULL after unplug */
> struct usb_device *udev;
>
> int type; /* type of cam (645, 646, 675, 680, 690, 720, 730, 740, 750) */
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