Re: [PATCH RFC] PCI: Convert devm_pci_alloc_host_bridge() users to error-pointer returns

[AngeloGioacchino Del Regno]

Il 21/09/25 18:14, Alok Tiwari ha scritto:
> devm_pci_alloc_host_bridge() and pci_alloc_host_bridge() previously
> returned NULL on failure, forcing callers to special-case NULL handling
> and often hardcode -ENOMEM as the error.
>
> This series updates devm_pci_alloc_host_bridge() to consistently return
> error pointers (ERR_PTR) with the actual error code, instead of NULL.
> All callers across PCI host controller drivers are updated to use
> IS_ERR_OR_NULL()/PTR_ERR() instead of NULL checks and hardcoded -ENOMEM.
>
> Benefits:
>    - Standardizes error handling with Linux kernel ERR_PTR()/PTR_ERR()
>      conventions.
>    - Ensures that the actual error code from lower-level helpers is
>      propagated back to the caller.
>    - Removes ambiguity between NULL and error pointer returns.
>
> Touched drivers include:
>   cadence (J721E, cadence-plat)
>   dwc (designware, qcom)
>   mobiveil (layerscape-gen4, mobiveil-plat)
>   aardvark, ftpci100, ixp4xx, loongson, mvebu, rcar, tegra, v3-semi,
>   versatile, xgene, altera, brcmstb, iproc, mediatek, mt7621, xilinx,
>   plda, and others
>
> This patch updates error handling across these host controller drivers
>   so that callers consistently receive ERR_PTR() instead of NULL.

I think that's a nice improvement - propagating the right error code looks good.

The only thing is - you have to make sure that it never returns NULL, so that
in the controller drivers you always check for `if (IS_ERR(x))` - otherwise with
the current IS_ERR_OR_NULL(x) most of the error paths are wrong.

Cheers,
Angelo

> Signed-off-by: Alok Tiwari <alok.a.tiwari@xxxxxxxxxx>
> ---
>   arch/mips/pci/pci-xtalk-bridge.c                       | 4 ++--
>   drivers/pci/controller/cadence/pci-j721e.c             | 4 ++--
>   drivers/pci/controller/cadence/pcie-cadence-plat.c     | 4 ++--
>   drivers/pci/controller/dwc/pcie-designware-host.c      | 4 ++--
>   drivers/pci/controller/dwc/pcie-qcom.c                 | 4 ++--
>   drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c | 4 ++--
>   drivers/pci/controller/mobiveil/pcie-mobiveil-plat.c   | 4 ++--
>   drivers/pci/controller/pci-aardvark.c                  | 4 ++--
>   drivers/pci/controller/pci-ftpci100.c                  | 4 ++--
>   drivers/pci/controller/pci-host-common.c               | 4 ++--
>   drivers/pci/controller/pci-hyperv.c                    | 4 ++--
>   drivers/pci/controller/pci-ixp4xx.c                    | 4 ++--
>   drivers/pci/controller/pci-loongson.c                  | 4 ++--
>   drivers/pci/controller/pci-mvebu.c                     | 4 ++--
>   drivers/pci/controller/pci-rcar-gen2.c                 | 4 ++--
>   drivers/pci/controller/pci-tegra.c                     | 4 ++--
>   drivers/pci/controller/pci-v3-semi.c                   | 4 ++--
>   drivers/pci/controller/pci-versatile.c                 | 4 ++--
>   drivers/pci/controller/pci-xgene.c                     | 4 ++--
>   drivers/pci/controller/pcie-altera.c                   | 4 ++--
>   drivers/pci/controller/pcie-brcmstb.c                  | 4 ++--
>   drivers/pci/controller/pcie-iproc-bcma.c               | 4 ++--
>   drivers/pci/controller/pcie-iproc-platform.c           | 4 ++--
>   drivers/pci/controller/pcie-mediatek-gen3.c            | 4 ++--
>   drivers/pci/controller/pcie-mediatek.c                 | 4 ++--
>   drivers/pci/controller/pcie-mt7621.c                   | 4 ++--
>   drivers/pci/controller/pcie-rcar-host.c                | 4 ++--
>   drivers/pci/controller/pcie-rockchip-host.c            | 4 ++--
>   drivers/pci/controller/pcie-xilinx-cpm.c               | 4 ++--
>   drivers/pci/controller/pcie-xilinx-dma-pl.c            | 4 ++--
>   drivers/pci/controller/pcie-xilinx-nwl.c               | 4 ++--
>   drivers/pci/controller/pcie-xilinx.c                   | 4 ++--
>   drivers/pci/controller/plda/pcie-plda-host.c           | 4 ++--
>   drivers/pci/probe.c                                    | 8 ++++----
>   34 files changed, 70 insertions(+), 70 deletions(-)