Re: [Xen-devel] Re: [PATCH 20/23] xen-pcifront: Xen PCI frontend driver.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Thu, Oct 14, 2010 at 08:15:06AM +0100, Jan Beulich wrote:
> >>> On 13.10.10 at 18:16, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> 
> >>> wrote:
> > On Wed, Oct 13, 2010 at 09:53:44AM -0400, Konrad Rzeszutek Wilk wrote:
> >> Hey Jan,
> >> 
> >> Thank you for taking your time to look at this patch. Will fix up, test 
> >> it, 
> >> and if there are no issues, have it ready tomorrow.
> > 
> > Attached (and inline) is the updated version of this patch. If I missed 
> > anything
> > please do point it out to me!
> 
> There's one more missing "static", and one incorrect change to
> free_pdev() you did.

Fixed.
> 
> Also, any word on the pdev_lock you dropped from the original
> implementation?

Yes. The reason for dropping it was that the xenwatch thread provides
the neccessary locking for the states. So no more need for this
spin_lock.

> 
> > If this is to your satisfaction, can I put a Reviewed-by tag on the patch?
> 
> Feel free to do so.

Thank you.
> 
> > --- /dev/null
> > +++ b/drivers/pci/xen-pcifront.c
> >...
> > +int __devinit pcifront_scan_bus(struct pcifront_device *pdev,
> 
> static?

Yup, done.
> 
> >...
> > +static void free_pdev(struct pcifront_device *pdev)
> > +{
> > +   dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
> > +
> > +   pcifront_free_roots(pdev);
> > +
> > +   /*For PCIE_AER error handling job*/
> > +   flush_scheduled_work();
> > +
> > +   if (pdev->irq)
> 
>       if (pdev->irq > 0)
> 
> It gets initialized to -1 in alloc_pdev(). It may be debatable whether
> it should be >= 0 - I'm not sure if the pv-ops code allows IRQ 0 to
> be used. If it doesn't, initializing to 0 in alloc_pdev() would be an
> alternative.

I made it '>=' The Xen PCI (arch/x86/pci/xen.c) and Xen Events 
(riers/xen/events.c)
are both OK with an IRQ of zero. So lets be uniform and be OK here too.

> 
> > +           unbind_from_irqhandler(pdev->irq, pdev);
> > +
> > +   if (pdev->evtchn != INVALID_EVTCHN)
> > +           xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
> > +
> > +   if (pdev->gnt_ref != INVALID_GRANT_REF)
> > +           gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
> > +                                     (unsigned long)pdev->sh_info);
> > +   else
> > +           free_page((unsigned long)pdev->sh_info);
> > +
> > +   dev_set_drvdata(&pdev->xdev->dev, NULL);
> > +
> > +   kfree(pdev);
> > +}
> > +
> > +static int pcifront_publish_info(struct pcifront_device *pdev)
> > +{
> > +   int err = 0;
> > +   struct xenbus_transaction trans;
> > +
> > +   err = xenbus_grant_ring(pdev->xdev, virt_to_mfn(pdev->sh_info));
> > +   if (err < 0)
> > +           goto out;
> > +
> > +   pdev->gnt_ref = err;
> > +
> > +   err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
> > +   if (err)
> > +           goto out;
> > +
> > +   err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
> > +           0, "pcifront", pdev);
> > +   if (err < 0) {
> > +           /*
> > +           xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
> > +           xenbus_dev_fatal(pdev->xdev, err, "Failed to bind evtchn to "
> > +                            "irqhandler.\n");
> > +           */
> 
> Why are you commenting it out rather than removing it?

Umm. I was in a hurry to test it out and just in case it would fail I
made it a comment. And then forgot about it. Removed that comented out
section of code.
> 
> Jan
> 
> 
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