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>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/media/video/videodev.c b/drivers/media/video/videodev.c
index 31e8af0ba278..e5679c28163f 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;
 }