From: Vincent Sanders <vince@simtec.co.uk>
Date: Sun, 6 Dec 2009 16:06:26 +0000 (+0100)
Subject: i2c: Remove big kernel lock from i2cdev_open
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9669f54194b4df34c96478d696d9ba2b977545f5;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

i2c: Remove big kernel lock from i2cdev_open

The BKL is held over a kmalloc so cannot protect anything beyond that.
The two calls before the kmalloc have their own locking.
Improve device open function by removing the now unnecessary ret variable

Signed-off-by: Vincent Sanders <vince@simtec.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
---

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 7e13d2df9af3..f4110aa49600 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -34,7 +34,6 @@
 #include <linux/list.h>
 #include <linux/i2c.h>
 #include <linux/i2c-dev.h>
-#include <linux/smp_lock.h>
 #include <linux/jiffies.h>
 #include <asm/uaccess.h>
 
@@ -445,20 +444,14 @@ 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) {
-		ret = -ENODEV;
-		goto out;
-	}
+	if (!i2c_dev)
+		return -ENODEV;
 
 	adap = i2c_get_adapter(i2c_dev->adap->nr);
-	if (!adap) {
-		ret = -ENODEV;
-		goto out;
-	}
+	if (!adap)
+		return -ENODEV;
 
 	/* This creates an anonymous i2c_client, which may later be
 	 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
@@ -470,8 +463,7 @@ static int i2cdev_open(struct inode *inode, struct file *file)
 	client = kzalloc(sizeof(*client), GFP_KERNEL);
 	if (!client) {
 		i2c_put_adapter(adap);
-		ret = -ENOMEM;
-		goto out;
+		return -ENOMEM;
 	}
 	snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
 	client->driver = &i2cdev_driver;
@@ -479,9 +471,7 @@ static int i2cdev_open(struct inode *inode, struct file *file)
 	client->adapter = adap;
 	file->private_data = client;
 
-out:
-	unlock_kernel();
-	return ret;
+	return 0;
 }
 
 static int i2cdev_release(struct inode *inode, struct file *file)