diff options
author | Hans Verkuil <hverkuil@xs4all.nl> | 2008-08-29 20:31:35 (GMT) |
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committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2008-10-12 11:36:56 (GMT) |
commit | 7f8ecfab7a1d256707502207c56dd4bf3e3a026e (patch) | |
tree | 2ba6079ba59017d03f53e0ba068e099008ef21d5 /drivers/media/video/v4l2-dev.c | |
parent | 187565c43a95bcf7798c58d518ddd765933d24da (diff) | |
download | linux-7f8ecfab7a1d256707502207c56dd4bf3e3a026e.tar.xz |
V4L/DVB (8852): v4l2: use register_chrdev_region instead of register_chrdev
Replace the old register_chrdev with the more flexible register_chrdev_region.
Ensure that the release() is called when the very last chardev usage was
released, and not when the sysfs devices were removed. This should simplify
hotpluggable drivers considerably.
Tested-by: Mike Isely <isely@isely.net>
Tested-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Acked-by: David Ellingsworth <david@identd.dyndns.org>
Reviewed-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/v4l2-dev.c')
-rw-r--r-- | drivers/media/video/v4l2-dev.c | 131 |
1 files changed, 63 insertions, 68 deletions
diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index 99f7ee4..02b9cc7 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -60,6 +60,12 @@ static struct device_attribute video_device_attrs[] = { __ATTR_NULL }; +/* + * Active devices + */ +static struct video_device *video_device[VIDEO_NUM_DEVICES]; +static DEFINE_MUTEX(videodev_lock); + struct video_device *video_device_alloc(void) { return kzalloc(sizeof(struct video_device), GFP_KERNEL); @@ -79,11 +85,41 @@ void video_device_release_empty(struct video_device *vfd) } 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) +{ + struct video_device *vfd = container_of(kobj, struct video_device, cdev.kobj); + + mutex_lock(&videodev_lock); + if (video_device[vfd->minor] != vfd) + panic("videodev: bad release"); + + /* Free up this device for reuse */ + video_device[vfd->minor] = NULL; + mutex_unlock(&videodev_lock); + + /* Release the character device */ + vfd->cdev_release(kobj); + /* Release video_device and perform other + cleanups as needed. */ + if (vfd->release) + vfd->release(vfd); +} + +/* The new kobj_type for the character device */ +static struct kobj_type v4l2_ktype_cdev_default = { + .release = v4l2_chardev_release, +}; + static void video_release(struct device *cd) { struct video_device *vfd = container_of(cd, struct video_device, dev); - vfd->release(vfd); + /* 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); } static struct class video_class = { @@ -92,56 +128,12 @@ static struct class video_class = { .dev_release = video_release, }; -/* - * Active devices - */ - -static struct video_device *video_device[VIDEO_NUM_DEVICES]; -static DEFINE_MUTEX(videodev_lock); - struct video_device *video_devdata(struct file *file) { return video_device[iminor(file->f_path.dentry->d_inode)]; } EXPORT_SYMBOL(video_devdata); -/* - * Open a video device - FIXME: Obsoleted - */ -static int video_open(struct inode *inode, struct file *file) -{ - unsigned int minor = iminor(inode); - int err = 0; - struct video_device *vfl; - const struct file_operations *old_fops; - - if (minor >= VIDEO_NUM_DEVICES) - return -ENODEV; - mutex_lock(&videodev_lock); - vfl = video_device[minor]; - if (vfl == NULL) { - mutex_unlock(&videodev_lock); - request_module("char-major-%d-%d", VIDEO_MAJOR, minor); - mutex_lock(&videodev_lock); - vfl = video_device[minor]; - if (vfl == NULL) { - mutex_unlock(&videodev_lock); - return -ENODEV; - } - } - old_fops = file->f_op; - file->f_op = fops_get(vfl->fops); - if (file->f_op->open) - err = file->f_op->open(inode, file); - if (err) { - fops_put(file->f_op); - file->f_op = fops_get(old_fops); - } - fops_put(old_fops); - mutex_unlock(&videodev_lock); - return err; -} - /** * get_index - assign stream number based on parent device * @vdev: video_device to assign index number to, vdev->dev should be assigned @@ -261,6 +253,9 @@ int video_register_device_index(struct video_device *vfd, int type, int nr, return -EINVAL; } + /* Initialize the character device */ + cdev_init(&vfd->cdev, vfd->fops); + vfd->cdev.owner = vfd->fops->owner; /* pick a minor number */ mutex_lock(&videodev_lock); if (nr >= 0 && nr < end-base) { @@ -294,6 +289,11 @@ int video_register_device_index(struct video_device *vfd, int type, int nr, goto fail_minor; } + ret = cdev_add(&vfd->cdev, MKDEV(VIDEO_MAJOR, vfd->minor), 1); + if (ret < 0) { + printk(KERN_ERR "%s: cdev_add failed\n", __func__); + goto fail_minor; + } /* sysfs class */ memset(&vfd->dev, 0, sizeof(vfd->dev)); /* The memset above cleared the device's drvdata, so @@ -307,11 +307,17 @@ int video_register_device_index(struct video_device *vfd, int type, int nr, ret = device_register(&vfd->dev); if (ret < 0) { printk(KERN_ERR "%s: device_register failed\n", __func__); - goto fail_minor; + goto del_cdev; } - + /* 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; +del_cdev: + cdev_del(&vfd->cdev); + fail_minor: mutex_lock(&videodev_lock); video_device[vfd->minor] = NULL; @@ -331,42 +337,29 @@ EXPORT_SYMBOL(video_register_device_index); void video_unregister_device(struct video_device *vfd) { - mutex_lock(&videodev_lock); - if (video_device[vfd->minor] != vfd) - panic("videodev: bad unregister"); - - video_device[vfd->minor] = NULL; device_unregister(&vfd->dev); - mutex_unlock(&videodev_lock); } EXPORT_SYMBOL(video_unregister_device); /* - * Video fs operations - */ -static const struct file_operations video_fops = { - .owner = THIS_MODULE, - .llseek = no_llseek, - .open = video_open, -}; - -/* * Initialise video for linux */ - static int __init videodev_init(void) { + dev_t dev = MKDEV(VIDEO_MAJOR, 0); int ret; printk(KERN_INFO "Linux video capture interface: v2.00\n"); - if (register_chrdev(VIDEO_MAJOR, VIDEO_NAME, &video_fops)) { - printk(KERN_WARNING "video_dev: unable to get major %d\n", VIDEO_MAJOR); - return -EIO; + ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME); + if (ret < 0) { + printk(KERN_WARNING "videodev: unable to get major %d\n", + VIDEO_MAJOR); + return ret; } ret = class_register(&video_class); if (ret < 0) { - unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME); + unregister_chrdev_region(dev, VIDEO_NUM_DEVICES); printk(KERN_WARNING "video_dev: class_register failed\n"); return -EIO; } @@ -376,8 +369,10 @@ static int __init videodev_init(void) static void __exit videodev_exit(void) { + dev_t dev = MKDEV(VIDEO_MAJOR, 0); + class_unregister(&video_class); - unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME); + unregister_chrdev_region(dev, VIDEO_NUM_DEVICES); } module_init(videodev_init) |