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Subject[PATCH] Remove big kernel lock use from i2cdev_open
Date
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>
---
drivers/i2c/i2c-dev.c | 21 ++++++---------------
1 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 7e13d2d..3196503 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -445,20 +445,14 @@ 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 +464,7 @@ 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 +472,7 @@ 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)
--
1.6.0.4


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