Re: [PATCH v2 00/10] Add definition for the number of standard PCI BARs

Bjorn Helgaas
2019-08-16T13:35:11Z

On Fri, Aug 16, 2019 at 11:51:28AM +0100, Andrew Murray wrote:
> On Fri, Aug 16, 2019 at 12:24:27PM +0300, Denis Efremov wrote:
> > Code that iterates over all standard PCI BARs typically uses
> > PCI_STD_RESOURCE_END, but this is error-prone because it requires
> > "i <= PCI_STD_RESOURCE_END" rather than something like
> > "i < PCI_STD_NUM_BARS". We could add such a definition and use it the same
> > way PCI_SRIOV_NUM_BARS is used. There is already the definition
> > PCI_BAR_COUNT for s390 only. Thus, this patchset introduces it globally.
> >
> > Changes in v2:
> > - Reverse checks in pci_iomap_range,pci_iomap_wc_range.
> > - Refactor loops in vfio_pci to keep PCI_STD_RESOURCES.
> > - Add 2 new patches to replace the magic constant with new define.
> > - Split net patch in v1 to separate stmmac and dwc-xlgmac patches.
> >
> > Denis Efremov (10):
> > PCI: Add define for the number of standard PCI BARs
> > s390/pci: Loop using PCI_STD_NUM_BARS
> > x86/PCI: Loop using PCI_STD_NUM_BARS
> > stmmac: pci: Loop using PCI_STD_NUM_BARS
> > net: dwc-xlgmac: Loop using PCI_STD_NUM_BARS
> > rapidio/tsi721: Loop using PCI_STD_NUM_BARS
> > efifb: Loop using PCI_STD_NUM_BARS
> > vfio_pci: Loop using PCI_STD_NUM_BARS
> > PCI: hv: Use PCI_STD_NUM_BARS
> > PCI: Use PCI_STD_NUM_BARS
> >
> > arch/s390/include/asm/pci.h | 5 +----
> > arch/s390/include/asm/pci_clp.h | 6 +++---
> > arch/s390/pci/pci.c | 16 ++++++++--------
> > arch/s390/pci/pci_clp.c | 6 +++---
> > arch/x86/pci/common.c | 2 +-
> > drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c | 4 ++--
> > drivers/net/ethernet/synopsys/dwc-xlgmac-pci.c | 2 +-
> > drivers/pci/controller/pci-hyperv.c | 10 +++++-----
> > drivers/pci/pci.c | 11 ++++++-----
> > drivers/pci/quirks.c | 4 ++--
> > drivers/rapidio/devices/tsi721.c | 2 +-
> > drivers/vfio/pci/vfio_pci.c | 11 +++++++----
> > drivers/vfio/pci/vfio_pci_config.c | 10 ++++++----
> > drivers/vfio/pci/vfio_pci_private.h | 4 ++--
> > drivers/video/fbdev/efifb.c | 2 +-
> > include/linux/pci.h | 2 +-
> > include/uapi/linux/pci_regs.h | 1 +
> > 17 files changed, 51 insertions(+), 47 deletions(-)
>
> I've come across a few more places where this change can be made. There
> may be multiple instances in the same file, but only the first is shown
> below:
>
> drivers/misc/pci_endpoint_test.c: for (bar = BAR_0; bar <= BAR_5; bar++) {
> drivers/net/ethernet/intel/e1000/e1000_main.c: for (i = BAR_1; i <= BAR_5; i++) {
> drivers/net/ethernet/intel/ixgb/ixgb_main.c: for (i = BAR_1; i <= BAR_5; i++) {
> drivers/pci/controller/dwc/pci-dra7xx.c: for (bar = BAR_0; bar <= BAR_5; bar++)
> drivers/pci/controller/dwc/pci-layerscape-ep.c: for (bar = BAR_0; bar <= BAR_5; bar++)
> drivers/pci/controller/dwc/pcie-artpec6.c: for (bar = BAR_0; bar <= BAR_5; bar++)
> drivers/pci/controller/dwc/pcie-designware-plat.c: for (bar = BAR_0; bar <= BAR_5; bar++)
> drivers/pci/endpoint/functions/pci-epf-test.c: for (bar = BAR_0; bar <= BAR_5; bar++) {
> include/linux/pci-epc.h: u64 bar_fixed_size[BAR_5 + 1];
> drivers/scsi/pm8001/pm8001_hwi.c: for (bar = 0; bar < 6; bar++) {
> drivers/scsi/pm8001/pm8001_init.c: for (bar = 0; bar < 6; bar++) {
> drivers/ata/sata_nv.c: for (bar = 0; bar < 6; bar++)
> drivers/video/fbdev/core/fbmem.c: for (idx = 0, bar = 0; bar < PCI_ROM_RESOURCE; bar++) {
> drivers/staging/gasket/gasket_core.c: for (i = 0; i < GASKET_NUM_BARS; i++) {
> drivers/tty/serial/8250/8250_pci.c: for (i = 0; i < PCI_NUM_BAR_RESOURCES; i++) { <-----------

Thanks, I agree, these look like good candidates as well.

> It looks like BARs are often iterated with PCI_NUM_BAR_RESOURCES, there
> are a load of these too found with:
>
> git grep PCI_ROM_RESOURCE | grep "< "

Good point, those are slightly questionable and I'd change those too.

Bjorn