linux-kernel - Re: [PATCH 2/3] pci: Add a generic, weakly-linked pcibios_align

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Date:   Sat, 24 Jun 2017 11:41:42 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Palmer Dabbelt <palmer@...belt.com>
Cc:     linux-pci <linux-pci@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Christoph Hellwig <hch@...radead.org>,
        Arnd Bergmann <arnd@...db.de>,
        arcml <linux-snps-arc@...ts.infradead.org>,
        Cris <linux-cris-kernel@...s.com>,
        "linux-ia64@...r.kernel.org" <linux-ia64@...r.kernel.org>,
        linux-s390 <linux-s390@...r.kernel.org>,
        Linux-sh list <linux-sh@...r.kernel.org>,
        sparclinux <sparclinux@...r.kernel.org>
Subject: Re: [PATCH 2/3] pci: Add a generic, weakly-linked pcibios_align_resource

Hi Palmer,

On Sat, Jun 24, 2017 at 3:50 AM, Palmer Dabbelt <palmer@...belt.com> wrote:
> Multiple architectures define this as trivial function, and I'm adding
> another one as part of the RISC-V port.  This adds a __weak version of
> pcibios_align_resource and deletes the now obselete ones in a handful of
> ports.
>
> The only functional change should be that a handful of ports used to
> export pcibios_fixup_bus.  Only some architectures export this, so I
> just dropped it.
>
> Signed-off-by: Palmer Dabbelt <palmer@...belt.com>

This function is only ever used as a pointer passed to
pci_bus_alloc_resource()?

What about having

    #ifndef pcibios_fixup_bus
    #define pcibios_fixup_bus NULL
    #endif

in asm-generic/pci.h, letting the architecture with a non-trivial
implementation predefine the preprocessor symbol, and teaching
pci_bus_alloc_resource() to handle NULL?

[...]

Oh, the latter eventually calls into allocate_resource(), which already falls
back to simple_align_resource() if the alignment function is NULL, which
does the same thing.
So NULL should already work.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

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