[media] pwc: better usb disconnect handling
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.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/pwc/pwc-if.c b/drivers/media/video/pwc/pwc-if.c
index 356cd42..b0bde5a 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 @@
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 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.
@@ -1016,16 +987,15 @@
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;
}
@@ -1033,19 +1003,17 @@
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
@@ -1106,7 +1074,7 @@
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);
}
}
@@ -1180,16 +1148,15 @@
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);
}
@@ -1199,7 +1166,7 @@
{
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);
@@ -1234,12 +1201,6 @@
}
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;
@@ -1715,19 +1676,12 @@
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);
@@ -1746,8 +1700,6 @@
}
}
- pdev->vdev->release = video_device_release;
-
/* occupy slot */
if (hint < MAX_DEV_HINTS)
device_hint[hint].pdev = pdev;
@@ -1759,16 +1711,16 @@
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 */
@@ -1776,7 +1728,7 @@
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;
}
@@ -1794,7 +1746,7 @@
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
@@ -1804,10 +1756,7 @@
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;
@@ -1816,10 +1765,8 @@
/* 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) {
@@ -1836,30 +1783,25 @@
}
/* 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");
+
+ /* No need to keep the urbs around after disconnection */
+ pwc_isoc_cleanup(pdev);
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;
- }
-
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
}