From 6606470dd1d628878383c96d10b52a77986ddac7 Mon Sep 17 00:00:00 2001
From: Jonathan Corbet <corbet@lwn.net>
Date: Fri, 16 May 2008 14:28:31 -0600
Subject: videodev: BKL pushdown

Put explicit lock_kernel() calls into videodev_open().  That function
itself seems OK, but one never knows about all the open() functions
provided by underlying video drivers.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

diff --git a/drivers/media/video/videodev.c b/drivers/media/video/videodev.c
index 31e8af0..e5679c2 100644
--- a/drivers/media/video/videodev.c
+++ b/drivers/media/video/videodev.c
@@ -36,6 +36,7 @@
 #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>
 
@@ -496,6 +497,7 @@ static int video_open(struct inode *inode, struct file *file)
 
 	if(minor>=VIDEO_NUM_DEVICES)
 		return -ENODEV;
+	lock_kernel();
 	mutex_lock(&videodev_lock);
 	vfl=video_device[minor];
 	if(vfl==NULL) {
@@ -505,6 +507,7 @@ static int video_open(struct inode *inode, struct file *file)
 		vfl=video_device[minor];
 		if (vfl==NULL) {
 			mutex_unlock(&videodev_lock);
+			unlock_kernel();
 			return -ENODEV;
 		}
 	}
@@ -518,6 +521,7 @@ static int video_open(struct inode *inode, struct file *file)
 	}
 	fops_put(old_fops);
 	mutex_unlock(&videodev_lock);
+	unlock_kernel();
 	return err;
 }
 
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