Re: [PATCH v5 1/2] ACPI: utils: Add api to read _SUB from ACPI

On Thu, Jun 30, 2022 at 5:17 PM Stefan Binding sbinding@opensource.cirrus.com wrote:

Add a wrapper function to read the _SUB string from ACPI.

...

•   if (obj->type == ACPI_TYPE_STRING) {
  

•           if (strlen(obj->string.pointer) < ACPI_MAX_SUB_BUF_SIZE &&
  

•               strlen(obj->string.pointer) > 0) {
  

•                   sub = kstrdup(obj->string.pointer, GFP_KERNEL);
  

•                   if (!sub)
  

•                           sub = ERR_PTR(-ENOMEM);
  

•           } else {
  

•                   acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n",
  

•                                   strlen(obj->string.pointer));
  

Three times to evaluate strlen()... Can we do better, please?

•                   sub = ERR_PTR(-EINVAL);
  

•           }
  

•   } else {
  

•           acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");
  

•           sub = ERR_PTR(-EINVAL);
  

•   }