phantom: BKL pushdown

Add explicit lock_kernel calls to phantom_open().

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

diff --git a/drivers/misc/phantom.c b/drivers/misc/phantom.c
index 71d1c84..1861624 100644 (file)
--- a/drivers/misc/phantom.c
+++ b/drivers/misc/phantom.c
@@ -22,6 +22,7 @@
 #include <linux/interrupt.h>
 #include <linux/cdev.h>
 #include <linux/phantom.h>
+#include <linux/smp_lock.h>
 
 #include <asm/atomic.h>
 #include <asm/io.h>
@@ -212,13 +213,17 @@ static int phantom_open(struct inode *inode, struct file *file)
        struct phantom_device *dev = container_of(inode->i_cdev,
                        struct phantom_device, cdev);
 
+       lock_kernel();
        nonseekable_open(inode, file);
 
-       if (mutex_lock_interruptible(&dev->open_lock))
+       if (mutex_lock_interruptible(&dev->open_lock)) {
+               unlock_kernel();
                return -ERESTARTSYS;
+       }
 
        if (dev->opened) {
                mutex_unlock(&dev->open_lock);
+               unlock_kernel();
                return -EINVAL;
        }
 
@@ -229,7 +234,7 @@ static int phantom_open(struct inode *inode, struct file *file)
        atomic_set(&dev->counter, 0);
        dev->opened++;
        mutex_unlock(&dev->open_lock);
-
+       unlock_kernel();
        return 0;
 }