Re: [PATCH] linux/pci.h: add a dummy implement for pci_clear_master()

[Geert Uytterhoeven]

Hi Sui,

On Tue, May 30, 2023 at 12:21 PM Sui Jingfeng <suijingfeng@xxxxxxxxxxx> wrote:
> As some arch(m68k for example) doesn't have config_pci enabled, drivers[1]
> call pci_clear_master() without config_pci guard can not built.
>
>    drivers/gpu/drm/etnaviv/etnaviv_pci_drv.c:
>    In function 'etnaviv_gpu_pci_fini':
> >> drivers/gpu/drm/etnaviv/etnaviv_pci_drv.c:32:9:
>    error: implicit declaration of function 'pci_clear_master';
>    did you mean 'pci_set_master'? [-Werror=implicit-function-declaration]
>       32 |         pci_clear_master(pdev);
>          |         ^~~~~~~~~~~~~~~~
>          |         pci_set_master
>    cc1: some warnings being treated as errors
>
> [1] https://patchwork.freedesktop.org/patch/539977/?series=118522&rev=1
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202305301659.4guSLavL-lkp@xxxxxxxxx/
> Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>

Thanks for your patch!

> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1904,6 +1904,7 @@ static inline int pci_dev_present(const struct pci_device_id *ids)
>  #define pci_dev_put(dev)       do { } while (0)
>
>  static inline void pci_set_master(struct pci_dev *dev) { }
> +static inline void pci_clear_master(struct pci_dev *dev) { }
>  static inline int pci_enable_device(struct pci_dev *dev) { return -EIO; }
>  static inline void pci_disable_device(struct pci_dev *dev) { }
>  static inline int pcim_enable_device(struct pci_dev *pdev) { return -EIO; }

Makes perfect sense, given there has been a dummy for pci_set_master()
since the git stone age. Apparently adding the dummy was forgotten
when pci_clear_master() was introduced.

Fixes: 6a479079c07211bf ("PCI: Add pci_clear_master() as opposite of
pci_set_master()")
Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds