diff mbox series

[v2,1/2] hwmon: (dell-smm) Simplify ioctl handler

Message ID 20211211155422.16830-2-W_Armin@gmx.de (mailing list archive)
State Accepted
Headers show
Series hwmon: (dell-smm) Improve ioctl handler | expand

Commit Message

Armin Wolf Dec. 11, 2021, 3:54 p.m. UTC 
The second switch-case has no real purpose:

- for I8K_BIOS_VERSION, val does not represent a return value,
  making the check for error values unnecessary.
- for I8K_MACHINE_ID, val remains zero, so the error check is
  unnecessary too.

Remove the switch-case and move the calls to copy_to_user()
into the first switch-case for I8K_BIOS_VERSION/_MACHINE_ID.
Omit buff[] since data->bios_machineid already contains the string
with the necessary zero padding through devm_kzalloc().

Tested on a Dell Inspiron 3505.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/hwmon/dell-smm-hwmon.c | 30 +++++++++---------------------
 1 file changed, 9 insertions(+), 21 deletions(-)

--
2.30.2

Comments

Pali Rohár Dec. 11, 2021, 4:04 p.m. UTC | #1 
On Saturday 11 December 2021 16:54:21 Armin Wolf wrote:
> The second switch-case has no real purpose:
> 
> - for I8K_BIOS_VERSION, val does not represent a return value,
>   making the check for error values unnecessary.
> - for I8K_MACHINE_ID, val remains zero, so the error check is
>   unnecessary too.
> 
> Remove the switch-case and move the calls to copy_to_user()
> into the first switch-case for I8K_BIOS_VERSION/_MACHINE_ID.
> Omit buff[] since data->bios_machineid already contains the string
> with the necessary zero padding through devm_kzalloc().
> 
> Tested on a Dell Inspiron 3505.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>

Reviewed-by: Pali Rohár <pali@kernel.org>

> ---
>  drivers/hwmon/dell-smm-hwmon.c | 30 +++++++++---------------------
>  1 file changed, 9 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
> index 5596c211f38d..186d40938036 100644
> --- a/drivers/hwmon/dell-smm-hwmon.c
> +++ b/drivers/hwmon/dell-smm-hwmon.c
> @@ -454,7 +454,6 @@ i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd
>  {
>  	int val = 0;
>  	int speed, err;
> -	unsigned char buff[16];
>  	int __user *argp = (int __user *)arg;
> 
>  	if (!argp)
> @@ -468,15 +467,19 @@ i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd
> 
>  		val = (data->bios_version[0] << 16) |
>  				(data->bios_version[1] << 8) | data->bios_version[2];
> -		break;
> 
> +		if (copy_to_user(argp, &val, sizeof(val)))
> +			return -EFAULT;
> +
> +		return 0;
>  	case I8K_MACHINE_ID:
>  		if (restricted && !capable(CAP_SYS_ADMIN))
>  			return -EPERM;
> 
> -		strscpy_pad(buff, data->bios_machineid, sizeof(buff));
> -		break;
> +		if (copy_to_user(argp, data->bios_machineid, sizeof(data->bios_machineid)))
> +			return -EFAULT;
> 
> +		return 0;
>  	case I8K_FN_STATUS:
>  		val = i8k_get_fn_status();
>  		break;
> @@ -527,23 +530,8 @@ i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd
>  	if (val < 0)
>  		return val;
> 
> -	switch (cmd) {
> -	case I8K_BIOS_VERSION:
> -		if (copy_to_user(argp, &val, 4))
> -			return -EFAULT;
> -
> -		break;
> -	case I8K_MACHINE_ID:
> -		if (copy_to_user(argp, buff, 16))
> -			return -EFAULT;
> -
> -		break;
> -	default:
> -		if (copy_to_user(argp, &val, sizeof(int)))
> -			return -EFAULT;
> -
> -		break;
> -	}
> +	if (copy_to_user(argp, &val, sizeof(int)))
> +		return -EFAULT;
> 
>  	return 0;
>  }
> --
> 2.30.2
>
Guenter Roeck Dec. 17, 2021, 3:37 p.m. UTC | #2 
On Sat, Dec 11, 2021 at 04:54:21PM +0100, Armin Wolf wrote:
> The second switch-case has no real purpose:
> 
> - for I8K_BIOS_VERSION, val does not represent a return value,
>   making the check for error values unnecessary.
> - for I8K_MACHINE_ID, val remains zero, so the error check is
>   unnecessary too.
> 
> Remove the switch-case and move the calls to copy_to_user()
> into the first switch-case for I8K_BIOS_VERSION/_MACHINE_ID.
> Omit buff[] since data->bios_machineid already contains the string
> with the necessary zero padding through devm_kzalloc().
> 
> Tested on a Dell Inspiron 3505.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> Reviewed-by: Pali Rohár <pali@kernel.org>

Series applied.

Thanks,
Guenter

> ---
>  drivers/hwmon/dell-smm-hwmon.c | 30 +++++++++---------------------
>  1 file changed, 9 insertions(+), 21 deletions(-)
> 
> --
> 2.30.2
> 
> diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
> index 5596c211f38d..186d40938036 100644
> --- a/drivers/hwmon/dell-smm-hwmon.c
> +++ b/drivers/hwmon/dell-smm-hwmon.c
> @@ -454,7 +454,6 @@ i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd
>  {
>  	int val = 0;
>  	int speed, err;
> -	unsigned char buff[16];
>  	int __user *argp = (int __user *)arg;
> 
>  	if (!argp)
> @@ -468,15 +467,19 @@ i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd
> 
>  		val = (data->bios_version[0] << 16) |
>  				(data->bios_version[1] << 8) | data->bios_version[2];
> -		break;
> 
> +		if (copy_to_user(argp, &val, sizeof(val)))
> +			return -EFAULT;
> +
> +		return 0;
>  	case I8K_MACHINE_ID:
>  		if (restricted && !capable(CAP_SYS_ADMIN))
>  			return -EPERM;
> 
> -		strscpy_pad(buff, data->bios_machineid, sizeof(buff));
> -		break;
> +		if (copy_to_user(argp, data->bios_machineid, sizeof(data->bios_machineid)))
> +			return -EFAULT;
> 
> +		return 0;
>  	case I8K_FN_STATUS:
>  		val = i8k_get_fn_status();
>  		break;
> @@ -527,23 +530,8 @@ i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd
>  	if (val < 0)
>  		return val;
> 
> -	switch (cmd) {
> -	case I8K_BIOS_VERSION:
> -		if (copy_to_user(argp, &val, 4))
> -			return -EFAULT;
> -
> -		break;
> -	case I8K_MACHINE_ID:
> -		if (copy_to_user(argp, buff, 16))
> -			return -EFAULT;
> -
> -		break;
> -	default:
> -		if (copy_to_user(argp, &val, sizeof(int)))
> -			return -EFAULT;
> -
> -		break;
> -	}
> +	if (copy_to_user(argp, &val, sizeof(int)))
> +		return -EFAULT;
> 
>  	return 0;
>  }
diff mbox series

Patch

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 5596c211f38d..186d40938036 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -454,7 +454,6 @@  i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd
 {
 	int val = 0;
 	int speed, err;
-	unsigned char buff[16];
 	int __user *argp = (int __user *)arg;

 	if (!argp)
@@ -468,15 +467,19 @@  i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd

 		val = (data->bios_version[0] << 16) |
 				(data->bios_version[1] << 8) | data->bios_version[2];
-		break;

+		if (copy_to_user(argp, &val, sizeof(val)))
+			return -EFAULT;
+
+		return 0;
 	case I8K_MACHINE_ID:
 		if (restricted && !capable(CAP_SYS_ADMIN))
 			return -EPERM;

-		strscpy_pad(buff, data->bios_machineid, sizeof(buff));
-		break;
+		if (copy_to_user(argp, data->bios_machineid, sizeof(data->bios_machineid)))
+			return -EFAULT;

+		return 0;
 	case I8K_FN_STATUS:
 		val = i8k_get_fn_status();
 		break;
@@ -527,23 +530,8 @@  i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd
 	if (val < 0)
 		return val;

-	switch (cmd) {
-	case I8K_BIOS_VERSION:
-		if (copy_to_user(argp, &val, 4))
-			return -EFAULT;
-
-		break;
-	case I8K_MACHINE_ID:
-		if (copy_to_user(argp, buff, 16))
-			return -EFAULT;
-
-		break;
-	default:
-		if (copy_to_user(argp, &val, sizeof(int)))
-			return -EFAULT;
-
-		break;
-	}
+	if (copy_to_user(argp, &val, sizeof(int)))
+		return -EFAULT;

 	return 0;
 }