Re: [PATCH 4/6] PCI/VGA: Move the new_state assignment out the loop

From: Bjorn Helgaas
Date: Tue Jul 25 2023 - 17:51:10 EST


On Mon, Jul 24, 2023 at 09:02:14PM +0800, suijingfeng wrote:
> PING, please !

Don't worry, these are not forgotten. Your other series seems more
important, so that's what I've been paying attention to.

> On 2023/7/11 21:43, Sui Jingfeng wrote:
> > From: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
> >
> > In the vga_arbiter_notify_clients() function, the value of the 'new_state'
> > variable will be 'false' on systems that have more than one PCI VGA card.
> > Its value will be 'true' on systems that have one or no PCI VGA compatible
> > card. In other words, its value is not relevant to the iteration, so move
> > the assignment () out of the loop.
> >
> > For a system with multiple video cards, this patch saves the redundant
> > assignment.
> >
> > Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
> > ---
> > drivers/pci/vgaarb.c | 16 +++++++---------
> > 1 file changed, 7 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
> > index 668139f7c247..4c448c758bab 100644
> > --- a/drivers/pci/vgaarb.c
> > +++ b/drivers/pci/vgaarb.c
> > @@ -1468,22 +1468,20 @@ static void vga_arbiter_notify_clients(void)
> > {
> > struct vga_device *vgadev;
> > unsigned long flags;
> > - uint32_t new_decodes;
> > - bool new_state;
> > + bool state;
> > if (!vga_arbiter_used)
> > return;
> > + state = (vga_count > 1) ? false : true;
> > +
> > spin_lock_irqsave(&vga_lock, flags);
> > list_for_each_entry(vgadev, &vga_list, list) {
> > - if (vga_count > 1)
> > - new_state = false;
> > - else
> > - new_state = true;
> > if (vgadev->set_decode) {
> > - new_decodes = vgadev->set_decode(vgadev->pdev,
> > - new_state);
> > - vga_update_device_decodes(vgadev, new_decodes);
> > + unsigned int decodes;
> > +
> > + decodes = vgadev->set_decode(vgadev->pdev, state);
> > + vga_update_device_decodes(vgadev, decodes);
> > }
> > }
> > spin_unlock_irqrestore(&vga_lock, flags);
>