v4l: Convert v4l2-dev to unlocked_ioctl

v4l2 implements two separate file operations for drivers that
use locked and unlocked ioctl callbacks. Since we want to remove
the ioctl file operation in favor of the unlocked variant, this
separation no longer seems helpful.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Cc: John Kacur <jkacur@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

drivers/media/video/v4l2-dev.c

@@ -25,6 +25,7 @@
 #include <linux/init.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>
 
@@ -215,28 +216,24 @@ static unsigned int v4l2_poll(struct file *filp, struct poll_table_struct *poll)
 	return vdev->fops->poll(filp, poll);
 }
 
-static int v4l2_ioctl(struct inode *inode, struct file *filp,
-		unsigned int cmd, unsigned long arg)
+static long v4l2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct video_device *vdev = video_devdata(filp);
+	int ret;
 
-	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(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) {
+		ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
+	} else if (vdev->fops->ioctl) {
+		/* TODO: convert all drivers to unlocked_ioctl */
+		lock_kernel();
+		ret = vdev->fops->ioctl(filp, cmd, arg);
+		unlock_kernel();
+	} else
+		ret = -ENOTTY;
 
-	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);
+	return ret;
 }
 
 #ifdef CONFIG_MMU
@@ -307,22 +304,6 @@ static int v4l2_release(struct inode *inode, struct file *filp)
 	return ret;
 }
 
-static const struct file_operations v4l2_unlocked_fops = {
-	.owner = THIS_MODULE,
-	.read = v4l2_read,
-	.write = v4l2_write,
-	.open = v4l2_open,
-	.get_unmapped_area = v4l2_get_unmapped_area,
-	.mmap = v4l2_mmap,
-	.unlocked_ioctl = v4l2_unlocked_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl = v4l2_compat_ioctl32,
-#endif
-	.release = v4l2_release,
-	.poll = v4l2_poll,
-	.llseek = no_llseek,
-};
-
 static const struct file_operations v4l2_fops = {
 	.owner = THIS_MODULE,
 	.read = v4l2_read,
@@ -330,7 +311,7 @@ static const struct file_operations v4l2_fops = {
 	.open = v4l2_open,
 	.get_unmapped_area = v4l2_get_unmapped_area,
 	.mmap = v4l2_mmap,
-	.ioctl = v4l2_ioctl,
+	.unlocked_ioctl = v4l2_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = v4l2_compat_ioctl32,
 #endif
@@ -521,10 +502,7 @@ static int __video_register_device(struct video_device *vdev, int type, int nr,
 		ret = -ENOMEM;
 		goto cleanup;
 	}
-	if (vdev->fops->unlocked_ioctl)
-		vdev->cdev->ops = &v4l2_unlocked_fops;
-	else
-		vdev->cdev->ops = &v4l2_fops;
+	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) {