Re: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null

[Mathias Nyman]

On 10.08.2017 03:35, Lu Baolu wrote:
> Hi,
>
> On 08/09/2017 03:58 PM, Mathias Nyman wrote:
> > On 27.07.2017 05:21, Lu Baolu wrote:
> > > xhci_disable_slot() is a helper for disabling a slot when a device
> > > goes away or recovers from error situations. Currently, it checks
> > > the corespoding virt-dev pointer and returns directly (w/o issuing
> > > disable slot command) if it's null.
> > >
> > > This is unnecessary and will cause problems in case where virt-dev
> > > allocation fails and xhci_disable_slot() is called to roll back the
> > > hardware state. Refer to the implementation of xhci_alloc_dev().
> >
> > True, checking for xhci->devs[slot_id] doesn't work if xhci_alloc_dev()
> > failed xhci_alloc_virt_device() and calls xhci_disable_slot,
> >
> > but the virt dev check is needed for test mode, which will just try
> > to disable all slots from 1 to HCS_MAX_SLOTS:
> >
> >   xhci_enter_test_mode(..)
> >         /* Disable all Device Slots */
> >      for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
> >                  retval = xhci_disable_slot(xhci, NULL, i);
>
> So, how about checking virt dev before this invoking?
>
> @@ -612,10 +612,12 @@ static int xhci_enter_test_mode(struct xhci_hcd *xhci,
>          xhci_dbg(xhci, "Disable all slots\n");
>          spin_unlock_irqrestore(&xhci->lock, *flags);
>          for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
> -               retval = xhci_disable_slot(xhci, NULL, i);
> -               if (retval)
> -                       xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
> -                                i, retval);
> +               if (xhci->devs[i]) {
> +                       retval = xhci_disable_slot(xhci, NULL, i);
> +                       if (retval)
> +                               xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
> +                                        i, retval);
> +               }


Yes, something like this will work

Thanks
Mathias