Re: [PATCH v6 00/11] PCI: Drop duplicated tracking of a pci_dev's bound driver

Bjorn Helgaas
2021-10-15T16:46:59Z

On Wed, Oct 13, 2021 at 04:23:09PM +0300, Andy Shevchenko wrote:
> On Wed, Oct 13, 2021 at 06:33:56AM -0500, Bjorn Helgaas wrote:
> > On Wed, Oct 13, 2021 at 12:26:42PM +0300, Andy Shevchenko wrote:
> > > On Wed, Oct 13, 2021 at 2:33 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > > > On Mon, Oct 04, 2021 at 02:59:24PM +0200, Uwe Kleine-König wrote:

> > > > + return drv && drv->resume ?
> > > > + drv->resume(pci_dev) : pci_pm_reenable_device(pci_dev);
> > >
> > > One line?
> >
> > I don't think I touched that line.
>
> Then why they are both in + section?

They're both in the + section of the interdiff because Uwe's v6 patch
looks like this:

static int pci_legacy_resume(struct device *dev)
{
struct pci_dev *pci_dev = to_pci_dev(dev);
- return drv && drv->resume ?
- drv->resume(pci_dev) : pci_pm_reenable_device(pci_dev);
+ if (pci_dev->dev.driver) {
+ struct pci_driver *drv = to_pci_driver(pci_dev->dev.driver);
+
+ if (drv->resume)
+ return drv->resume(pci_dev);
+ }
+
+ return pci_pm_reenable_device(pci_dev);

and my revision looks like this:

static int pci_legacy_resume(struct device *dev)
{
struct pci_dev *pci_dev = to_pci_dev(dev);
- struct pci_driver *drv = pci_dev->driver;
+ struct pci_driver *drv = to_pci_driver(dev->driver);

so compared to Uwe's v6, I restored that section to the original code.
My goal here was to make the patch as simple and easy to review as
possible.

> > > > + struct pci_driver *drv = to_pci_driver(dev->dev.driver);
> > > > const struct pci_error_handlers *err_handler =
> > > > - dev->dev.driver ? to_pci_driver(dev->dev.driver)->err_handler : NULL;
> > > > + drv ? drv->err_handler : NULL;
> > >
> > > Isn't dev->driver == to_pci_driver(dev->dev.driver)?
> >
> > Yes, I think so, but not sure what you're getting at here, can you
> > elaborate?
>
> Getting pointer from another pointer seems waste of resources, why we
> can't simply
>
> struct pci_driver *drv = dev->driver;

I think this is in pci_dev_save_and_disable(), and "dev" here is a
struct pci_dev *. We're removing the dev->driver member. Let me know
if I'm still missing something.

> > > > - "bad request in aer recovery "
> > > > - "operation!\n");
> > > > + "bad request in AER recovery operation!\n");

> > > Stray change? Or is it in a separate patch in your tree?
> >
> > Could be skipped. The string now fits on one line so I combined it to
> > make it more greppable.
>
> This is inconsistency in your changes, in one case you are objecting of
> doing something close to the changed lines, in the other you are doing
> unrelated change.

You're right, this didn't make much sense in that patch. I moved the
line join to the previous patch, which unindented this section and
made space for this to fit on one line. Here's the revised commit: