diff options
| -rw-r--r-- | drivers/media/video/v4l2-dev.c | 356 | ||||
| -rw-r--r-- | include/media/v4l2-dev.h | 47 |
2 files changed, 295 insertions, 108 deletions
diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index c5ca51a..4e0db88 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -41,17 +41,17 @@ static ssize_t show_index(struct device *cd, struct device_attribute *attr, char *buf) { - struct video_device *vfd = container_of(cd, struct video_device, dev); + struct video_device *vdev = to_video_device(cd); - return sprintf(buf, "%i\n", vfd->index); + return sprintf(buf, "%i\n", vdev->index); } static ssize_t show_name(struct device *cd, struct device_attribute *attr, char *buf) { - struct video_device *vfd = container_of(cd, struct video_device, dev); + struct video_device *vdev = to_video_device(cd); - return sprintf(buf, "%.*s\n", (int)sizeof(vfd->name), vfd->name); + return sprintf(buf, "%.*s\n", (int)sizeof(vdev->name), vdev->name); } static struct device_attribute video_device_attrs[] = { @@ -73,64 +73,64 @@ struct video_device *video_device_alloc(void) } EXPORT_SYMBOL(video_device_alloc); -void video_device_release(struct video_device *vfd) +void video_device_release(struct video_device *vdev) { - kfree(vfd); + kfree(vdev); } EXPORT_SYMBOL(video_device_release); -void video_device_release_empty(struct video_device *vfd) +void video_device_release_empty(struct video_device *vdev) { /* Do nothing */ /* Only valid when the video_device struct is a static. */ } EXPORT_SYMBOL(video_device_release_empty); -/* Called when the last user of the character device is gone. */ -static void v4l2_chardev_release(struct kobject *kobj) +static inline void video_get(struct video_device *vdev) { - struct video_device *vfd = container_of(kobj, struct video_device, cdev.kobj); + get_device(&vdev->dev); +} + +static inline void video_put(struct video_device *vdev) +{ + put_device(&vdev->dev); +} + +/* Called when the last user of the video device exits. */ +static void v4l2_device_release(struct device *cd) +{ + struct video_device *vdev = to_video_device(cd); mutex_lock(&videodev_lock); - if (video_device[vfd->minor] != vfd) { + if (video_device[vdev->minor] != vdev) { mutex_unlock(&videodev_lock); - BUG(); + /* should not happen */ + WARN_ON(1); return; } /* Free up this device for reuse */ - video_device[vfd->minor] = NULL; - clear_bit(vfd->num, video_nums[vfd->vfl_type]); - mutex_unlock(&videodev_lock); + video_device[vdev->minor] = NULL; - /* Release the character device */ - vfd->cdev_release(kobj); - /* Release video_device and perform other - cleanups as needed. */ - if (vfd->release) - vfd->release(vfd); -} + /* Delete the cdev on this minor as well */ + cdev_del(vdev->cdev); + /* Just in case some driver tries to access this from + the release() callback. */ + vdev->cdev = NULL; -/* The new kobj_type for the character device */ -static struct kobj_type v4l2_ktype_cdev_default = { - .release = v4l2_chardev_release, -}; + /* Mark minor as free */ + clear_bit(vdev->num, video_nums[vdev->vfl_type]); -static void video_release(struct device *cd) -{ - struct video_device *vfd = container_of(cd, struct video_device, dev); + mutex_unlock(&videodev_lock); - /* It's now safe to delete the char device. - This will either trigger the v4l2_chardev_release immediately (if - the refcount goes to 0) or later when the last user of the - character device closes it. */ - cdev_del(&vfd->cdev); + /* Release video_device and perform other + cleanups as needed. */ + vdev->release(vdev); } static struct class video_class = { .name = VIDEO_NAME, .dev_attrs = video_device_attrs, - .dev_release = video_release, }; struct video_device *video_devdata(struct file *file) @@ -139,13 +139,163 @@ struct video_device *video_devdata(struct file *file) } EXPORT_SYMBOL(video_devdata); +static ssize_t v4l2_read(struct file *filp, char __user *buf, + size_t sz, loff_t *off) +{ + struct video_device *vdev = video_devdata(filp); + + if (!vdev->fops->read) + return -EINVAL; + if (video_is_unregistered(vdev)) + return -EIO; + return vdev->fops->read(filp, buf, sz, off); +} + +static ssize_t v4l2_write(struct file *filp, const char __user *buf, + size_t sz, loff_t *off) +{ + struct video_device *vdev = video_devdata(filp); + + if (!vdev->fops->write) + return -EINVAL; + if (video_is_unregistered(vdev)) + return -EIO; + return vdev->fops->write(filp, buf, sz, off); +} + +static unsigned int v4l2_poll(struct file *filp, struct poll_table_struct *poll) +{ + struct video_device *vdev = video_devdata(filp); + + if (!vdev->fops->poll || video_is_unregistered(vdev)) + return DEFAULT_POLLMASK; + return vdev->fops->poll(filp, poll); +} + +static int v4l2_ioctl(struct inode *inode, struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct video_device *vdev = video_devdata(filp); + + if (!vdev->fops->ioctl) + return -ENOTTY; + /* Allow ioctl to continue even if the device was unregistered. + Things like dequeueing buffers might still be useful. */ + return vdev->fops->ioctl(inode, filp, cmd, arg); +} + +static long v4l2_unlocked_ioctl(struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct video_device *vdev = video_devdata(filp); + + if (!vdev->fops->unlocked_ioctl) + return -ENOTTY; + /* Allow ioctl to continue even if the device was unregistered. + Things like dequeueing buffers might still be useful. */ + return vdev->fops->unlocked_ioctl(filp, cmd, arg); +} + +#ifdef CONFIG_COMPAT +static long v4l2_compat_ioctl(struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct video_device *vdev = video_devdata(filp); + + if (!vdev->fops->compat_ioctl) + return -ENOIOCTLCMD; + /* Allow ioctl to continue even if the device was unregistered. + Things like dequeueing buffers might still be useful. */ + return vdev->fops->compat_ioctl(filp, cmd, arg); +} +#endif + +static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm) +{ + struct video_device *vdev = video_devdata(filp); + + if (!vdev->fops->mmap || + video_is_unregistered(vdev)) + return -ENODEV; + return vdev->fops->mmap(filp, vm); +} + +/* Override for the open function */ +static int v4l2_open(struct inode *inode, struct file *filp) +{ + struct video_device *vdev; + int ret; + + /* Check if the video device is available */ + mutex_lock(&videodev_lock); + vdev = video_devdata(filp); + /* return ENODEV if the video device has been removed + already or if it is not registered anymore. */ + if (vdev == NULL || video_is_unregistered(vdev)) { + mutex_unlock(&videodev_lock); + return -ENODEV; + } + /* and increase the device refcount */ + video_get(vdev); + mutex_unlock(&videodev_lock); + ret = vdev->fops->open(inode, filp); + /* decrease the refcount in case of an error */ + if (ret) + video_put(vdev); + return ret; +} + +/* Override for the release function */ +static int v4l2_release(struct inode *inode, struct file *filp) +{ + struct video_device *vdev = video_devdata(filp); + int ret = vdev->fops->release(inode, filp); + + /* decrease the refcount unconditionally since the release() + return value is ignored. */ + video_put(vdev); + return ret; +} + +static const struct file_operations v4l2_unlocked_fops = { + .owner = THIS_MODULE, + .read = v4l2_read, + .write = v4l2_write, + .open = v4l2_open, + .mmap = v4l2_mmap, + .unlocked_ioctl = v4l2_unlocked_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = v4l2_compat_ioctl, +#endif + .release = v4l2_release, + .poll = v4l2_poll, + .llseek = no_llseek, +}; + +static const struct file_operations v4l2_fops = { + .owner = THIS_MODULE, + .read = v4l2_read, + .write = v4l2_write, + .open = v4l2_open, + .mmap = v4l2_mmap, + .ioctl = v4l2_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = v4l2_compat_ioctl, +#endif + .release = v4l2_release, + .poll = v4l2_poll, + .llseek = no_llseek, +}; + /** * get_index - assign stream number based on parent device - * @vdev: video_device to assign index number to, vdev->dev should be assigned - * @num: -1 if auto assign, requested number otherwise + * @vdev: video_device to assign index number to, vdev->parent should be assigned + * @num: -1 if auto assign, requested number otherwise * + * Note that when this is called the new device has not yet been registered + * in the video_device array. * - * returns -ENFILE if num is already in use, a free index number if + * Returns -ENFILE if num is already in use, a free index number if * successful. */ static int get_index(struct video_device *vdev, int num) @@ -168,7 +318,6 @@ static int get_index(struct video_device *vdev, int num) for (i = 0; i < VIDEO_NUM_DEVICES; i++) { if (video_device[i] != NULL && - video_device[i] != vdev && video_device[i]->parent == vdev->parent) { used |= 1 << video_device[i]->index; } @@ -184,17 +333,15 @@ static int get_index(struct video_device *vdev, int num) return i > max_index ? -ENFILE : i; } -static const struct file_operations video_fops; - -int video_register_device(struct video_device *vfd, int type, int nr) +int video_register_device(struct video_device *vdev, int type, int nr) { - return video_register_device_index(vfd, type, nr, -1); + return video_register_device_index(vdev, type, nr, -1); } EXPORT_SYMBOL(video_register_device); /** * video_register_device_index - register video4linux devices - * @vfd: video device structure we want to register + * @vdev: video device structure we want to register * @type: type of device to register * @nr: which device number (0 == /dev/video0, 1 == /dev/video1, ... * -1 == first free) @@ -218,8 +365,7 @@ EXPORT_SYMBOL(video_register_device); * * %VFL_TYPE_RADIO - A radio card */ - -int video_register_device_index(struct video_device *vfd, int type, int nr, +int video_register_device_index(struct video_device *vdev, int type, int nr, int index) { int i = 0; @@ -227,14 +373,19 @@ int video_register_device_index(struct video_device *vfd, int type, int nr, int minor_offset = 0; int minor_cnt = VIDEO_NUM_DEVICES; const char *name_base; - void *priv = video_get_drvdata(vfd); + void *priv = video_get_drvdata(vdev); - /* the release callback MUST be present */ - BUG_ON(!vfd->release); + /* A minor value of -1 marks this video device as never + having been registered */ + if (vdev) + vdev->minor = -1; - if (vfd == NULL) + /* the release callback MUST be present */ + WARN_ON(!vdev || !vdev->release); + if (!vdev || !vdev->release) return -EINVAL; + /* Part 1: check device type */ switch (type) { case VFL_TYPE_GRABBER: name_base = "video"; @@ -254,8 +405,10 @@ int video_register_device_index(struct video_device *vfd, int type, int nr, return -EINVAL; } - vfd->vfl_type = type; + vdev->vfl_type = type; + vdev->cdev = NULL; + /* Part 2: find a free minor, kernel number and device index. */ #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES /* Keep the ranges for the first four types for historical * reasons. @@ -286,10 +439,7 @@ int video_register_device_index(struct video_device *vfd, int type, int nr, } #endif - /* Initialize the character device */ - cdev_init(&vfd->cdev, vfd->fops); - vfd->cdev.owner = vfd->fops->owner; - /* pick a minor number */ + /* Pick a minor number */ mutex_lock(&videodev_lock); nr = find_next_zero_bit(video_nums[type], minor_cnt, nr == -1 ? 0 : nr); if (nr == minor_cnt) @@ -313,72 +463,92 @@ int video_register_device_index(struct video_device *vfd, int type, int nr, return -ENFILE; } #endif - vfd->minor = i + minor_offset; - vfd->num = nr; + vdev->minor = i + minor_offset; + vdev->num = nr; set_bit(nr, video_nums[type]); - BUG_ON(video_device[vfd->minor]); - video_device[vfd->minor] = vfd; - - ret = get_index(vfd, index); - vfd->index = ret; - + /* Should not happen since we thought this minor was free */ + WARN_ON(video_device[vdev->minor] != NULL); + ret = vdev->index = get_index(vdev, index); mutex_unlock(&videodev_lock); if (ret < 0) { printk(KERN_ERR "%s: get_index failed\n", __func__); - goto fail_minor; + goto cleanup; } - ret = cdev_add(&vfd->cdev, MKDEV(VIDEO_MAJOR, vfd->minor), 1); + /* Part 3: Initialize the character device */ + vdev->cdev = cdev_alloc(); + if (vdev->cdev == NULL) { + ret = -ENOMEM; + goto cleanup; + } + if (vdev->fops->unlocked_ioctl) + vdev->cdev->ops = &v4l2_unlocked_fops; + else + vdev->cdev->ops = &v4l2_fops; + vdev->cdev->owner = vdev->fops->owner; + ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1); if (ret < 0) { printk(KERN_ERR "%s: cdev_add failed\n", __func__); - goto fail_minor; + kfree(vdev->cdev); + vdev->cdev = NULL; + goto cleanup; } - /* sysfs class */ - memset(&vfd->dev, 0, sizeof(vfd->dev)); + + /* Part 4: register the device with sysfs */ + memset(&vdev->dev, 0, sizeof(vdev->dev)); /* The memset above cleared the device's drvdata, so put back the copy we made earlier. */ - video_set_drvdata(vfd, priv); - vfd->dev.class = &video_class; - vfd->dev.devt = MKDEV(VIDEO_MAJOR, vfd->minor); - if (vfd->parent) - vfd->dev.parent = vfd->parent; - dev_set_name(&vfd->dev, "%s%d", name_base, nr); - ret = device_register(&vfd->dev); + video_set_drvdata(vdev, priv); + vdev->dev.class = &video_class; + vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor); + if (vdev->parent) + vdev->dev.parent = vdev->parent; + dev_set_name(&vdev->dev, "%s%d", name_base, nr); + ret = device_register(&vdev->dev); if (ret < 0) { printk(KERN_ERR "%s: device_register failed\n", __func__); - goto del_cdev; + goto cleanup; } - /* Remember the cdev's release function */ - vfd->cdev_release = vfd->cdev.kobj.ktype->release; - /* Install our own */ - vfd->cdev.kobj.ktype = &v4l2_ktype_cdev_default; - return 0; + /* Register the release callback that will be called when the last + reference to the device goes away. */ + vdev->dev.release = v4l2_device_release; -del_cdev: - cdev_del(&vfd->cdev); + /* Part 5: Activate this minor. The char device can now be used. */ + mutex_lock(&videodev_lock); + video_device[vdev->minor] = vdev; + mutex_unlock(&videodev_lock); + return 0; -fail_minor: +cleanup: mutex_lock(&videodev_lock); - video_device[vfd->minor] = NULL; - clear_bit(vfd->num, video_nums[type]); + if (vdev->cdev) + cdev_del(vdev->cdev); + clear_bit(vdev->num, video_nums[type]); mutex_unlock(&videodev_lock); - vfd->minor = -1; + /* Mark this video device as never having been registered. */ + vdev->minor = -1; return ret; } EXPORT_SYMBOL(video_register_device_index); /** * video_unregister_device - unregister a video4linux device - * @vfd: the device to unregister + * @vdev: the device to unregister * - * This unregisters the passed device and deassigns the minor - * number. Future open calls will be met with errors. + * This unregisters the passed device. Future open calls will + * be met with errors. */ - -void video_unregister_device(struct video_device *vfd) +void video_unregister_device(struct video_device *vdev) { - device_unregister(&vfd->dev); + /* Check if vdev was ever registered at all */ + if (!vdev || vdev->minor < 0) + return; + + mutex_lock(&videodev_lock); + set_bit(V4L2_FL_UNREGISTERED, &vdev->flags); + mutex_unlock(&videodev_lock); + device_unregister(&vdev->dev); } EXPORT_SYMBOL(video_unregister_device); diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h index a0a6b41..e0d72d2 100644 --- a/include/media/v4l2-dev.h +++ b/include/media/v4l2-dev.h @@ -26,6 +26,11 @@ struct v4l2_ioctl_callbacks; +/* Flag to mark the video_device struct as unregistered. + Drivers can set this flag if they want to block all future + device access. It is set by video_unregister_device. */ +#define V4L2_FL_UNREGISTERED (0) + /* * Newer version of video_device, handled by videodev2.c * This version moves redundant code from video device code to @@ -39,15 +44,17 @@ struct video_device /* sysfs */ struct device dev; /* v4l device */ - struct cdev cdev; /* character device */ - void (*cdev_release)(struct kobject *kobj); + struct cdev *cdev; /* character device */ struct device *parent; /* device parent */ /* device info */ char name[32]; int vfl_type; + /* 'minor' is set to -1 if the registration failed */ int minor; u16 num; + /* use bitops to set/clear/test flags */ + unsigned long flags; /* attribute to differentiate multiple indices on one physical device */ int index; @@ -58,7 +65,7 @@ struct video_device v4l2_std_id current_norm; /* Current tvnorm */ /* callbacks */ - void (*release)(struct video_device *vfd); + void (*release)(struct video_device *vdev); /* ioctl callbacks */ const struct v4l2_ioctl_ops *ioctl_ops; @@ -67,36 +74,41 @@ struct video_device /* dev to video-device */ #define to_video_device(cd) container_of(cd, struct video_device, dev) -/* Register and unregister devices. Note that if video_register_device fails, +/* Register video devices. Note that if video_register_device fails, the release() callback of the video_device structure is *not* called, so the caller is responsible for freeing any data. Usually that means that - you call video_device_release() on failure. */ -int __must_check video_register_device(struct video_device *vfd, int type, int nr); -int __must_check video_register_device_index(struct video_device *vfd, + you call video_device_release() on failure. + + Also note that vdev->minor is set to -1 if the registration failed. */ +int __must_check video_register_device(struct video_device *vdev, int type, int nr); +int __must_check video_register_device_index(struct video_device *vdev, int type, int nr, int index); -void video_unregister_device(struct video_device *vfd); + +/* Unregister video devices. Will do nothing if vdev == NULL or + vdev->minor < 0. */ +void video_unregister_device(struct video_device *vdev); /* helper functions to alloc/release struct video_device, the latter can also be used for video_device->release(). */ struct video_device * __must_check video_device_alloc(void); -/* this release function frees the vfd pointer */ -void video_device_release(struct video_device *vfd); +/* this release function frees the vdev pointer */ +void video_device_release(struct video_device *vdev); /* this release function does nothing, use when the video_device is a static global struct. Note that having a static video_device is a dubious construction at best. */ -void video_device_release_empty(struct video_device *vfd); +void video_device_release_empty(struct video_device *vdev); /* helper functions to access driver private data. */ -static inline void *video_get_drvdata(struct video_device *dev) +static inline void *video_get_drvdata(struct video_device *vdev) { - return dev_get_drvdata(&dev->dev); + return dev_get_drvdata(&vdev->dev); } -static inline void video_set_drvdata(struct video_device *dev, void *data) +static inline void video_set_drvdata(struct video_device *vdev, void *data) { - dev_set_drvdata(&dev->dev, data); + dev_set_drvdata(&vdev->dev, data); } struct video_device *video_devdata(struct file *file); @@ -108,4 +120,9 @@ static inline void *video_drvdata(struct file *file) return video_get_drvdata(video_devdata(file)); } +static inline int video_is_unregistered(struct video_device *vdev) +{ + return test_bit(V4L2_FL_UNREGISTERED, &vdev->flags); +} + #endif /* _V4L2_DEV_H */ |
