On 8/1/20 2:56 PM, Borislav Petkov wrote:
On Sat, Aug 01, 2020 at 01:24:29PM +0200, Saheed O. Bolarinwa wrote:The return value of pci_read_config_*() may not indicate a device error. However, the value read by these functions is more likely to indicate this kind of error. This presents two overlapping ways of reporting errors and complicates error checking.So why isn't the *value check done in the pci_read_config_* functions instead of touching gazillion callers?
Because the value ~0 has a meaning to some drivers and only drivers have this knowledge. For those cases more checks will be needed to ensure that it is an error that has actually happened.
For example, pci_conf{1,2}_read() could check whether the u32 *value it
just read depending on the access method, whether that value is ~0 and
return proper PCIBIOS_ error in that case.
The primary goal is to make pci_config_read*() return void, so that there is *only* one way to check for error i.e. through the obtained value. Again, only the drivers can determine if ~0 is a valid value. This information is not available inside pci_config_read*(). - Saheed
