[PATCH,RFC] Drop non-unlocked ioctl support in v4l2-dev.c

[Laurent Pinchart]

Hi everybody,

this patch moves the BKL one level down by removing the non-unlocked ioctl in
v4l2-dev.c and calling lock_kernel/unlock_kernel in the unlocked_ioctl handler
if the driver only supports locked ioctl.

Opinions/comments/applause/kicks ?

Regards,

Laurent Pinchart

diff -r 4533a406fddb linux/drivers/media/video/v4l2-dev.c
--- a/linux/drivers/media/video/v4l2-dev.c      Thu Aug 06 16:41:17 2009 +0200
+++ b/linux/drivers/media/video/v4l2-dev.c      Thu Aug 06 17:04:37 2009 +0200
@@ -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>
 
@@ -211,28 +212,22 @@
        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(filp, cmd, arg);
-}
-
 static long v4l2_unlocked_ioctl(struct file *filp,
                unsigned int cmd, unsigned long arg)
 {
        struct video_device *vdev = video_devdata(filp);
+       int 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);
+       if (vdev->fops->ioctl) {
+               lock_kernel();
+               ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
+               unlock_kernel();
+       } else if (vdev->fops->unlocked_ioctl)
+               ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
+
+       return ret;
 }
 
 #ifdef CONFIG_MMU
@@ -320,22 +315,6 @@
        .llseek = no_llseek,
 };
 
-static const struct file_operations v4l2_fops = {
-       .owner = THIS_MODULE,
-       .read = v4l2_read,
-       .write = v4l2_write,
-       .open = v4l2_open,
-       .get_unmapped_area = v4l2_get_unmapped_area,
-       .mmap = v4l2_mmap,
-       .ioctl = v4l2_ioctl,
-#ifdef CONFIG_COMPAT
-       .compat_ioctl = v4l2_compat_ioctl32,
-#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->parent should be 
assigned
@@ -534,15 +513,9 @@
                goto cleanup;
        }
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 17)
-       if (vdev->fops->unlocked_ioctl)
-               vdev->cdev->ops = &v4l2_unlocked_fops;
-       else
-               vdev->cdev->ops = &v4l2_fops;
+       vdev->cdev->ops = &v4l2_unlocked_fops;
 #else
-       if (vdev->fops->unlocked_ioctl)
-               vdev->cdev->ops = (struct file_operations *)&v4l2_unlocked_fops;
-       else
-               vdev->cdev->ops = (struct file_operations *)&v4l2_fops;
+       vdev->cdev->ops = (struct file_operations *)&v4l2_unlocked_fops;
 #endif
        vdev->cdev->owner = vdev->fops->owner;
        ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);

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