commit 4541b5ec9f631a143cdea862d07ddfc3cdac36f2
author Jonathan Corbet <corbet@lwn.net> Fri May 16 14:03:05 2008 -0600
committer Jonathan Corbet <corbet@lwn.net> Fri Jun 20 14:05:51 2008 -0600
tree 1b14d1f481c20790e7577b31fa76fb3952205cf8
parent 057e7c7ff9f91a36a761588c53826bd6a710aeba

phantom: BKL pushdown

Add explicit lock_kernel calls to phantom_open().

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

drivers/misc/phantom.c

diff --git a/drivers/misc/phantom.c b/drivers/misc/phantom.c
index 71d1c84..1861624 100644
--- 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 @@
 	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 @@
 	atomic_set(&dev->counter, 0);
 	dev->opened++;
 	mutex_unlock(&dev->open_lock);
-
+	unlock_kernel();
 	return 0;
 }