Subject: ~~

From: "Keller, Jacob E" <[email-masked]>
Date: Thu, 21 Jul 2016 20:13:03 +0000

On Thu, 2016-07-21 at 13:51 +0300, Sergei Shtylyov wrote:
> Hello.
> 
> On 7/21/2016 1:23 AM, Jeff Kirsher wrote:
> 
> > From: Jacob Keller <[email-masked]>
> > 
> > Sometimes, a VF driver will lose PCIe address access, such as due
> > to
> > a PF FLR event. In fm10k_detach_subtask, poll and check whether the
> > PCIe register space is active again and restore the device when it
> > has.
> > 
> > Signed-off-by: Jacob Keller <[email-masked]>
> > Tested-by: Krishneil Singh <[email-masked]>
> > Signed-off-by: Jeff Kirsher <[email-masked]>
> > ---
> >  drivers/net/ethernet/intel/fm10k/fm10k_pci.c | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> > 
> > diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
> > b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
> > index 5e40460..d4ccb2a 100644
> > --- a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
> > +++ b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
> > @@ -123,11 +123,24 @@ static void fm10k_service_timer(unsigned long
> > data)
> >  static void fm10k_detach_subtask(struct fm10k_intfc *interface)
> >  {
> >  	struct net_device *netdev = interface->netdev;
> > +	u32 __iomem *hw_addr;
> > +	u32 value;
> > 
> >  	/* do nothing if device is still present or hw_addr is set
> > */
> >  	if (netif_device_present(netdev) || interface->hw.hw_addr)
> >  		return;
> > 
> > +	/* check the real address space to see if we've recovered
> > */
> > +	hw_addr = READ_ONCE(interface->uc_addr);
> > +	value = readl(hw_addr);
> > +	if ((~value)) {
> 
>     Why these double parens?
> 

You're right it doesn't need them. I think at one point the check was
"!(~value)" in some other portion of code, and likely got copied by
mistake.

Thanks,
Jake

> [...]
> MBR, Sergei