Re: [PATCH v6 5/9] ACPI: APEI: EINJ: Enable the discovery of EINJv2 capabilities

["Luck, Tony" <tony.luck@xxxxxxxxx>]

On Thu, Apr 17, 2025 at 03:00:15PM -0700, Zaid Alali wrote:
> +static ssize_t error_type_set(struct file *file, const char __user *buf,
> +				size_t count, loff_t *ppos)
>  {
>  	int rc;
> +	u64 val;
> +
> +	memset(einj_buf, 0, sizeof(einj_buf));
> +	if (copy_from_user(einj_buf, buf, count))
> +		return -EFAULT;
> +
> +	if (strncmp(einj_buf, "V2_", 3) == 0) {

It's twice as common in Linux kernel code to see string equality checked with:

	if (!strncmp(einj_buf, "V2_", 3))

> +		if (!sscanf(einj_buf, "V2_%llx", &val))

More comprehensive error checking with this:

		ret = kstrtoull(einj_buf + 3, 16, &val);
		if (!ret)
			return -EINVAL;

> +			return -EINVAL;
> +	} else {
> +		if (!sscanf(einj_buf, "%llx", &val))

Ditto kstrtoull() use.

> +			return -EINVAL;
> +	}
>  
>  	rc = einj_validate_error_type(val);
>  	if (rc)
> @@ -722,11 +767,13 @@ static int error_type_set(void *data, u64 val)
>  
>  	error_type = val;
>  
> -	return 0;
> +	return count;
>  }