| Date | Sat, 10 Oct 2009 15:37:17 -0000 | From | Thomas Gleixner <> | Subject | [patch 23/28] i2c: Remove big kernel lock from i2cdev_open |
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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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