Re: [PATCH v2 08/13] PCI/portdrv: Simplify PCIe feature permission checking

[Bjorn Helgaas]

On Mon, Mar 12, 2018 at 01:04:02AM -0700, Christoph Hellwig wrote:
> > +	 * We assume we can manage these PCIe features.  Some systems may
> > +	 * reserve these for use by the platform itself, e.g., an ACPI BIOS
> > +	 * may implement its own AER handling and use _OSC to prevent the
> > +	 * OS from interfering.
> > +	 */
> > +	bridge->use_aer = 1;
> > +	bridge->use_hotplug = 1;
> > +	bridge->use_pme = 1;
> 
> If we start out with enabled maybe these should be disable_foo flags
> instead?

I went back and forth on that.  "disable_foo" is nice because the
default value is correct (zero means enabled).  But then you end up
with things like:

  if (pcie_ports_native || !host->disable_hotplug)

where the "!host->disable_hotplug" is a double negative, and I have a
really hard time reading that.

> Also please use bool (or a bitfield bool) for true/false values.

I'm a little ambivalent about bool in structs because of things like
this:

  https://lkml.kernel.org/r/CA+55aFxnePDimkVKVtv3gNmRGcwc8KQ5mHYvUxY8sAQg6yvVYg@xxxxxxxxxxxxxx

Bjorn