Re: linux-next: build failure after merge of the akpm tree

[Arjun Roy <arjunroy@google.com>]

On Sun, Feb 16, 2020 at 7:57 PM Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> Hi all,
>
> After merging the akpm tree, today's linux-next build (sparc64 defconfig)
> failed like this:
>
> mm/memory.c: In function 'insert_pages':
> mm/memory.c:1523:56: error: macro "pte_index" requires 2 arguments, but only 1 given
>    remaining_pages_total, PTRS_PER_PTE - pte_index(addr));
>                                                         ^
>
> Caused by commit
>
>   366142f0b000 ("mm/memory.c: add vm_insert_pages()")
>
> This is the first use of pte_index() outside arch specific code and the
> sparc64 version of pte_index() nas an extra argument.
>

Looks like this happens for sparc, and also metag. Other platforms
just take the addr parameter based on a quick search.

> I have reverted these commits for today:
>
>   219ae14a9686 ("net-zerocopy-use-vm_insert_pages-for-tcp-rcv-zerocopy-fix")
>   cb912fdf96bf ("net-zerocopy: use vm_insert_pages() for tcp rcv zerocopy")
>   72c684430b94 ("add missing page_count() check to vm_insert_pages().")
>   dbd9553775f3 ("mm-add-vm_insert_pages-fix")
>   366142f0b000 ("mm/memory.c: add vm_insert_pages()")
>

In terms of fixing this; passing in an appropriate dir parameter is
not really a problem, but what is concerning that it seems messy to
have a per-platform ifdef to pass it either two arguments or one in
this case. But it seems like either that would be one way to fix it,
or having some arch method across all arches that takes two arguments
(and ignores one of them for most arches).

Is there a general preference for the right way forward, in this case?

Thanks,
-Arjun

> --
> Cheers,
> Stephen Rothwell