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V4L/DVB (10641): v4l2-dev: remove limit of 32 devices per driver in get_index()

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get_index() had a limitation of 32 devices per driver. This was
unnecessarily strict and has been replaced with the maximum number
of devices. That should really satisfy anyone!

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2009-02-14 11:31:01 -03:00 committed by Mauro Carvalho Chehab
parent 27d35fc3fb
commit 775a05dd54
1 changed files with 13 additions and 12 deletions
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25
drivers/media/video/v4l2-dev.c
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@ -288,37 +288,38 @@ static const struct file_operations v4l2_fops = {
*/ */
static int get_index(struct video_device *vdev, int num) static int get_index(struct video_device *vdev, int num)
{ {
u32 used = 0; /* This can be static since this function is called with the global
const int max_index = sizeof(used) * 8 - 1; videodev_lock held. */
static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
int i; int i;
/* Currently a single v4l driver instance cannot create more than if (num >= VIDEO_NUM_DEVICES) {
32 devices.
Increase to u64 or an array of u32 if more are needed. */
if (num > max_index) {
printk(KERN_ERR "videodev: %s num is too large\n", __func__); printk(KERN_ERR "videodev: %s num is too large\n", __func__);
return -EINVAL; return -EINVAL;
} }
/* Some drivers do not set the parent. In that case always return 0. */ /* Some drivers do not set the parent. In that case always return
num or 0. */
if (vdev->parent == NULL) if (vdev->parent == NULL)
return 0; return num >= 0 ? num : 0;
bitmap_zero(used, VIDEO_NUM_DEVICES);
for (i = 0; i < VIDEO_NUM_DEVICES; i++) { for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
if (video_device[i] != NULL && if (video_device[i] != NULL &&
video_device[i]->parent == vdev->parent) { video_device[i]->parent == vdev->parent) {
used |= 1 << video_device[i]->index; set_bit(video_device[i]->index, used);
} }
} }
if (num >= 0) { if (num >= 0) {
if (used & (1 << num)) if (test_bit(num, used))
return -ENFILE; return -ENFILE;
return num; return num;
} }
i = ffz(used); i = find_first_zero_bit(used, VIDEO_NUM_DEVICES);
return i > max_index ? -ENFILE : i; return i == VIDEO_NUM_DEVICES ? -ENFILE : i;
} }
int video_register_device(struct video_device *vdev, int type, int nr) int video_register_device(struct video_device *vdev, int type, int nr)