Re: [Xen-devel] [PATCH V3 1/2] Drivers/PCI: Export pcie_has_flr() interface

[Govinda Tatti]

> > > > -static bool pcie_has_flr(struct pci_dev *dev)
> > > > +bool pcie_has_flr(struct pci_dev *dev)
> > > >   {
> > > >   	u32 cap;
> > > > @@ -3882,6 +3882,7 @@ static bool pcie_has_flr(struct pci_dev *dev)
> > > >   	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
> > > >   	return cap & PCI_EXP_DEVCAP_FLR;
> > > >   }
> > > > +EXPORT_SYMBOL_GPL(pcie_has_flr);
> > > I'd rather change pcie_flr() so you could *always* call it, and it
> > > would return 0, -ENOTTY, or whatever, based on whether FLR is
> > > supported.  Is that feasible?
> > Sure, I will add pcie_has_flr() logic inside pcie_flr() and return
> > appropriate
> > values as suggested by you. Do we still want to retain pcie_has_flr() and
> > its usage inside pci.c?.Otherwise, I will remove it and do required cleanup.
> If you can restructure the code and remove pcie_has_flr() while
> retaining the existing behavior of its callers, that would be great.
I checked the current usage of pcie_has_flr() and pcie_flr(). I have a 
couple
of questions or need some clarification.

1. pcie_has_flr() usage inside pci_probe_reset_function().

ÂÂ This function is only calling pcie_has_flr() but not pcie_flr().
ÂÂ Rest of the code is trying to do specific type of reset except 
pcie_flr().

ÂÂÂÂÂÂÂ rc = pci_dev_specific_reset(dev, 1);
ÂÂÂÂÂÂÂ if (rc != -ENOTTY)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return rc;
ÂÂÂÂÂÂÂ if (pcie_has_flr(dev))
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return 0;
ÂÂÂÂÂÂÂ rc = pci_af_flr(dev, 1);
ÂÂÂÂÂÂÂ if (rc != -ENOTTY)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return rc;

ÂÂ In other-words, I can remove usage of pcie_has_flr() in all other places
ÂÂ in pci.c except in above function.

2. W.r.t pcie_flr(), I am planning to return error code. Currently, the 
following
ÂÂ file/modules are calling this function. My plan is to add a check 
for return
ÂÂ code and print a WANRING message if return code is NON-ZERO. I hope 
this is
ÂÂ sufficient for this patch.

ÂÂ drivers/crypto/qat/qat_common/adf_aer.c
ÂÂ drivers/infiniband/hw/hfi1/chip.c (2 places)
ÂÂ drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
ÂÂ drivers/net/ethernet/intel/ixgbe/ixgbe_main.c (2 places)
ÂÂ drivers/pci/quirks.c (2 places)

Cheers
GOVINDA