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i2c: dev: Check for I2C_FUNC_I2C before calling i2c_transfer

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It is good practice to check that the underlying adapter supports
I2C transfers before attempting them. The i2c core would eventually
return an error, but it's more efficient to fail early.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This commit is contained in:
Jean Delvare 2024-05-31 11:34:07 +02:00 committed by Wolfram Sang
parent d08ed10623
commit 97ca843f6a
1 changed files with 12 additions and 0 deletions
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12
drivers/i2c/i2c-dev.c
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@ -139,6 +139,10 @@ static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
struct i2c_client *client = file->private_data; struct i2c_client *client = file->private_data;
/* Adapter must support I2C transfers */
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -EOPNOTSUPP;
if (count > 8192) if (count > 8192)
count = 8192; count = 8192;
@ -163,6 +167,10 @@ static ssize_t i2cdev_write(struct file *file, const char __user *buf,
char *tmp; char *tmp;
struct i2c_client *client = file->private_data; struct i2c_client *client = file->private_data;
/* Adapter must support I2C transfers */
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -EOPNOTSUPP;
if (count > 8192) if (count > 8192)
count = 8192; count = 8192;
@ -238,6 +246,10 @@ static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
u8 __user **data_ptrs; u8 __user **data_ptrs;
int i, res; int i, res;
/* Adapter must support I2C transfers */
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -EOPNOTSUPP;
data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL); data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
if (data_ptrs == NULL) { if (data_ptrs == NULL) {
kfree(msgs); kfree(msgs);