diff options
| -rw-r--r-- | drivers/media/video/v4l2-dev.c | 53 |
1 files changed, 48 insertions, 5 deletions
diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index 4e61c77..4715f08 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -68,6 +68,48 @@ static struct video_device *video_device[VIDEO_NUM_DEVICES]; static DEFINE_MUTEX(videodev_lock); static DECLARE_BITMAP(devnode_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES); +/* Device node utility functions */ + +/* Note: these utility functions all assume that vfl_type is in the range + [0, VFL_TYPE_MAX-1]. */ + +#ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES +/* Return the bitmap corresponding to vfl_type. */ +static inline unsigned long *devnode_bits(int vfl_type) +{ + /* Any types not assigned to fixed minor ranges must be mapped to + one single bitmap for the purposes of finding a free node number + since all those unassigned types use the same minor range. */ + int idx = (vfl_type > VFL_TYPE_VTX) ? VFL_TYPE_MAX - 1 : vfl_type; + + return devnode_nums[idx]; +} +#else +/* Return the bitmap corresponding to vfl_type. */ +static inline unsigned long *devnode_bits(int vfl_type) +{ + return devnode_nums[vfl_type]; +} +#endif + +/* Mark device node number vdev->num as used */ +static inline void devnode_set(struct video_device *vdev) +{ + set_bit(vdev->num, devnode_bits(vdev->vfl_type)); +} + +/* Mark device node number vdev->num as unused */ +static inline void devnode_clear(struct video_device *vdev) +{ + clear_bit(vdev->num, devnode_bits(vdev->vfl_type)); +} + +/* Try to find a free device node number in the range [from, to> */ +static inline int devnode_find(struct video_device *vdev, int from, int to) +{ + return find_next_zero_bit(devnode_bits(vdev->vfl_type), to, from); +} + struct video_device *video_device_alloc(void) { return kzalloc(sizeof(struct video_device), GFP_KERNEL); @@ -120,7 +162,7 @@ static void v4l2_device_release(struct device *cd) vdev->cdev = NULL; /* Mark device node number as free */ - clear_bit(vdev->num, devnode_nums[vdev->vfl_type]); + devnode_clear(vdev); mutex_unlock(&videodev_lock); @@ -435,9 +477,9 @@ int video_register_device(struct video_device *vdev, int type, int nr) /* Pick a device node number */ mutex_lock(&videodev_lock); - nr = find_next_zero_bit(devnode_nums[type], minor_cnt, nr == -1 ? 0 : nr); + nr = devnode_find(vdev, nr == -1 ? 0 : nr, minor_cnt); if (nr == minor_cnt) - nr = find_first_zero_bit(devnode_nums[type], minor_cnt); + nr = devnode_find(vdev, 0, minor_cnt); if (nr == minor_cnt) { printk(KERN_ERR "could not get a free device node number\n"); mutex_unlock(&videodev_lock); @@ -460,7 +502,8 @@ int video_register_device(struct video_device *vdev, int type, int nr) #endif vdev->minor = i + minor_offset; vdev->num = nr; - set_bit(nr, devnode_nums[type]); + devnode_set(vdev); + /* Should not happen since we thought this minor was free */ WARN_ON(video_device[vdev->minor] != NULL); vdev->index = get_index(vdev); @@ -514,7 +557,7 @@ cleanup: mutex_lock(&videodev_lock); if (vdev->cdev) cdev_del(vdev->cdev); - clear_bit(vdev->num, devnode_nums[type]); + devnode_clear(vdev); mutex_unlock(&videodev_lock); /* Mark this video device as never having been registered. */ vdev->minor = -1; |
