Re: [RESEND PATCH 00/16] PCI: Use FIELD_MODIFY() to simplify bitfield operations

[Bjorn Helgaas]

On Fri, May 01, 2026 at 12:24:04AM +0800, Hans Zhang wrote:
> Replace open-coded bitmask clear + FIELD_PREP() sequences with the
> dedicated FIELD_MODIFY() macro.  FIELD_MODIFY() performs the same
> operation but is shorter, less error-prone, and includes compile-time
> checks to prevent field overflow.
> 
> This series touches the PCI core, PCIe extended capabilities (PTM, IDE,
> TPH, MSI, REBAR, IOV, CardBus), and several DesignWare-based and
> other PCI host controllers.  No functional change is intended.
> 
> The patches are split per subsystem or per driver to ease review:
> ---
> Hi, If the Maintainers think it's not necessary, please ignore it.
> ---
> 
> Hans Zhang (16):
>   PCI: Use FIELD_MODIFY()
>   PCI/PTM: Use FIELD_MODIFY()
>   PCI/IDE: Use FIELD_MODIFY()
>   PCI/IOV: Use FIELD_MODIFY()
>   PCI/TPH: Use FIELD_MODIFY()
>   PCI/MSI: Use FIELD_MODIFY()
>   PCI/REBAR: Use FIELD_MODIFY()
>   PCI/CARDBUS: Use FIELD_MODIFY()
>   PCI: al: Use FIELD_MODIFY()
>   PCI: eswin: Use FIELD_MODIFY()
>   PCI: s32g: Use FIELD_MODIFY()
>   PCI: tegra194: Use FIELD_MODIFY()
>   PCI: qcom: Use FIELD_MODIFY()
>   PCI: dwc: Use FIELD_MODIFY()
>   PCI: mvebu: Use FIELD_MODIFY()
>   PCI: mediatek-gen3: Use FIELD_MODIFY()
> 
>  drivers/pci/controller/dwc/pcie-al.c          | 12 ++----
>  .../controller/dwc/pcie-designware-debugfs.c  | 23 ++++-------
>  .../pci/controller/dwc/pcie-designware-ep.c   |  3 +-
>  drivers/pci/controller/dwc/pcie-designware.c  |  3 +-
>  drivers/pci/controller/dwc/pcie-eswin.c       |  3 +-
>  drivers/pci/controller/dwc/pcie-nxp-s32g.c    |  3 +-
>  drivers/pci/controller/dwc/pcie-qcom-common.c | 40 +++++++------------
>  drivers/pci/controller/dwc/pcie-qcom-ep.c     |  6 +--
>  drivers/pci/controller/dwc/pcie-tegra194.c    |  8 ++--
>  drivers/pci/controller/pci-mvebu.c            |  3 +-
>  drivers/pci/controller/pcie-mediatek-gen3.c   |  3 +-
>  drivers/pci/ide.c                             |  6 +--
>  drivers/pci/iov.c                             |  3 +-
>  drivers/pci/msi/msi.c                         | 11 ++---
>  drivers/pci/pci.c                             |  3 +-
>  drivers/pci/pcie/ptm.c                        |  3 +-
>  drivers/pci/rebar.c                           |  6 +--
>  drivers/pci/setup-cardbus.c                   |  3 +-
>  drivers/pci/tph.c                             | 10 ++---
>  19 files changed, 51 insertions(+), 101 deletions(-)

I squashed these together since they're all doing exactly the same
thing and applied to pci/misc for v7.2, thanks!  I think this makes it
noticeably easier to read, especially in the cases where we update
several register fields at once.

Sashiko noticed the dev->sriov->barsz[] array bounds issue, which is
mostly addressed by another pending patch: https://patch.msgid.link/44a4ae53ec2825816b816c85cd378430d9a95cc6.1776429882.git.mnencia@xxxxxxxx

Sashiko also flagged a potential pcie-mediatek-gen3.c issue related to
checking the return from pci_runtime_get_sync(), but that has nothing
to do with this patch, so I'll just forward that to the Mediatek
folks.

https://sashiko.dev/#/patchset/20260430162420.42839-1-18255117159%40163.com