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

[Sui Jingfeng]

Hi,

On 2023/6/7 02:46, Bjorn Helgaas wrote:
> On Wed, Jun 07, 2023 at 01:48:38AM +0800, Sui Jingfeng wrote:
> > On 2023/6/7 00:13, Bjorn Helgaas wrote:
> > > On Tue, May 30, 2023 at 06:16:55PM +0800, Sui Jingfeng 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>
> > > I applied this to pci/misc for v6.5, with commit log as below.
> > >
> > > But I suspect that it might make your life easier if you include it
> > > with your etnaviv series.  You may be able to avoid adding the
> > > CONFIG_DRM_ETNAVIV_PCI_DRIVER symbol.
> > >
> > > If so, feel free to include this patch in that series with my ack:
> > >
> > > Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > I do want add this tag to my all  of the patches in the drm/etnaviv series,
> > thanks.
> >
> > and I really love you this idea.
> Just to be clear, my ack only applies to the addition of the
> pci_clear_master() stub in pci.h.  It does not apply to the patches in
> the drm/etnaviv series at
> https://lore.kernel.org/r/20230603105943.3042766-1-15330273260@xxxxxx
Ok, I understand what you meant then.
> > > If you do include it in your series, please use the commit log below
> > > and let me know so I can drop it from my queue.
> > No, please keep this patch merged by you.
> >
> > Because this patch belong to drivers/pci, Its belong to you domain.
> >
> >
> > I might choose to  remove the CONFIG_DRM_ETNAVIV_PCI_DRIVER option at next
> > version
> >
> > of my drm/etnaviv patch If it arrived to drm/tip branch.
> >
> >
> > But I guess some reviewers may still prefer a CONFIG_DRM_ETNAVIV_PCI_DRIVER
> > option,
> >
> > depend on the attitude of etnaviv folks.
> The purpose of my ack is to enable you to merge the patch along with
> the series that uses it.  This is a normal way of handling things that
> cross subsystem boundaries, so you don't need to feel uncomfortable
> about it.
>
> It is much more difficult to remove config options than it is to add
> them, because you must ensure that the removal doesn't break old
> .config files.
>
> I will keep this patch in my queue unless you tell me to drop it.
>
> Bjorn
>
> > >     Author: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
> > >     Date:   Wed May 31 18:27:44 2023 +0800
> > >
> > >       PCI: Add pci_clear_master() stub for non-CONFIG_PCI
> > >       Add a pci_clear_master() stub when CONFIG_PCI is not set so drivers that
> > >       support both PCI and platform devices don't need #ifdefs or extra Kconfig
> > >       symbols for the PCI parts.
> > >       [bhelgaas: commit log]
> > >       Fixes: 6a479079c072 ("PCI: Add pci_clear_master() as opposite of pci_set_master()")
> > >       Link: https://lore.kernel.org/r/20230531102744.2354313-1-suijingfeng@xxxxxxxxxxx
> > >       Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
> > >       Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > >       Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > >
> > > > ---
> > > >    include/linux/pci.h | 1 +
> > > >    1 file changed, 1 insertion(+)
> > > >
> > > > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > > > index d0c19ff0c958..71c85380676c 100644
> > > > --- 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; }
> > > > --
> > > > 2.25.1
> > --
> > Jingfeng
--
Jingfeng