Re: [PATCH v6 2/8] PCI/VGA: Deal only with VGA class devices

[Sui Jingfeng]

Hi,

On 2023/6/20 02:12, Limonciello, Mario wrote:
> On 6/12/2023 2:25 PM, Sui Jingfeng wrote:
> > From: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
> >
> > Deal only with the VGA devcie(pdev->class == 0x0300), so replace the
> > pci_get_subsys() function with pci_get_class(). Filter the non-PCI 
> > display
> > device(pdev->class != 0x0300) out. There no need to process the 
> > non-display
> > PCI device.
> >
> > Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
> > ---
> This also means that deleting a PCI device no longer needs
> to walk the list.
>
> Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>

Thanks a lot.


> >   drivers/pci/vgaarb.c | 22 ++++++++++++----------
> >   1 file changed, 12 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
> > index c1bc6c983932..22a505e877dc 100644
> > --- a/drivers/pci/vgaarb.c
> > +++ b/drivers/pci/vgaarb.c
> > @@ -754,10 +754,6 @@ static bool vga_arbiter_add_pci_device(struct 
> > pci_dev *pdev)
> >       struct pci_dev *bridge;
> >       u16 cmd;
> >   -    /* Only deal with VGA class devices */
> > -    if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
> > -        return false;
> > -
> >       /* Allocate structure */
> >       vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL);
> >       if (vgadev == NULL) {
> > @@ -1500,7 +1496,9 @@ static int pci_notify(struct notifier_block 
> > *nb, unsigned long action,
> >       struct pci_dev *pdev = to_pci_dev(dev);
> >       bool notify = false;
> >   -    vgaarb_dbg(dev, "%s\n", __func__);
> > +    /* Only deal with VGA class devices */
> > +    if (pdev->class != PCI_CLASS_DISPLAY_VGA << 8)
> > +        return 0;
> >         /* For now we're only intereted in devices added and removed. 
> > I didn't
> >        * test this thing here, so someone needs to double check for the
> > @@ -1510,6 +1508,8 @@ static int pci_notify(struct notifier_block 
> > *nb, unsigned long action,
> >       else if (action == BUS_NOTIFY_DEL_DEVICE)
> >           notify = vga_arbiter_del_pci_device(pdev);
> >   +    vgaarb_dbg(dev, "%s: action = %lu\n", __func__, action);
> > +
> >       if (notify)
> >           vga_arbiter_notify_clients();
> >       return 0;
> > @@ -1534,8 +1534,8 @@ static struct miscdevice vga_arb_device = {
> >     static int __init vga_arb_device_init(void)
> >   {
> > +    struct pci_dev *pdev = NULL;
> >       int rc;
> > -    struct pci_dev *pdev;
> >         rc = misc_register(&vga_arb_device);
> >       if (rc < 0)
> > @@ -1545,11 +1545,13 @@ static int __init vga_arb_device_init(void)
> >         /* We add all PCI devices satisfying VGA class in the arbiter by
> >        * default */
> > -    pdev = NULL;
> > -    while ((pdev =
> > -        pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
> > -                   PCI_ANY_ID, pdev)) != NULL)
> > +    while (1) {
> > +        pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev);
> > +        if (!pdev)
> > +            break;
> > +
> >           vga_arbiter_add_pci_device(pdev);
> > +    }
> >         pr_info("loaded\n");
> >       return rc;