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Subject[patch 23/28] 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>
LKML-Reference: <1255175172-2666-1-git-send-email-vince@simtec.co.uk>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
drivers/i2c/i2c-dev.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)

Index: linux-2.6-tip/drivers/i2c/i2c-dev.c
===================================================================
--- linux-2.6-tip.orig/drivers/i2c/i2c-dev.c
+++ linux-2.6-tip/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 *ino
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 *ino
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 *ino
client->adapter = adap;
file->private_data = client;

-out:
- unlock_kernel();
- return ret;
+ return 0;
}

static int i2cdev_release(struct inode *inode, struct file *file)



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