i2c: cdev lock_kernel() pushdown

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

drivers/i2c/i2c-dev.c

@@ -34,6 +34,7 @@
 #include <linux/list.h>
 #include <linux/i2c.h>
 #include <linux/i2c-dev.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 
 static struct i2c_driver i2cdev_driver;
@@ -441,14 +442,20 @@ static int i2cdev_open(struct inode *inode, struct file *file)
 	struct i2c_client *client;
 	struct i2c_adapter *adap;
 	struct i2c_dev *i2c_dev;
+	int ret = 0;
 
+	lock_kernel();
 	i2c_dev = i2c_dev_get_by_minor(minor);
-	if (!i2c_dev)
-		return -ENODEV;
+	if (!i2c_dev) {
+		ret = -ENODEV;
+		goto out;
+	}
 
 	adap = i2c_get_adapter(i2c_dev->adap->nr);
-	if (!adap)
-		return -ENODEV;
+	if (!adap) {
+		ret = -ENODEV;
+		goto out;
+	}
 
 	/* This creates an anonymous i2c_client, which may later be
 	 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
@@ -460,7 +467,8 @@ static int i2cdev_open(struct inode *inode, struct file *file)
 	client = kzalloc(sizeof(*client), GFP_KERNEL);
 	if (!client) {
 		i2c_put_adapter(adap);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto out;
 	}
 	snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
 	client->driver = &i2cdev_driver;
@@ -468,7 +476,9 @@ static int i2cdev_open(struct inode *inode, struct file *file)
 	client->adapter = adap;
 	file->private_data = client;
 
-	return 0;
+out:
+	unlock_kernel();
+	return ret;
 }
 
 static int i2cdev_release(struct inode *inode, struct file *file)