Re: [PATCH] ppc64: update to use the new 4L headers

[Nick Piggin]

Chris Friesen wrote:
> Nick Piggin wrote:
>
> > Just a bit off-topic: I wonder how many more of these open
> > coded pt walks exist in arch code (yes I see you've cleaned
> > yours up - good).
>
>
> I know there's open coded walks outside the tree (I maintain one) due to 
> there being no suitable function available from with in it...

Oh - I meant hand calculating the addresses rather than using
the pmd_addr_end and friends... but:

> I needed something like:
>
> pte_t *va_to_ptep_map(struct mm_struct *mm, unsigned int addr)
>
> There was code in follow_page() that did basically what I needed, but it 
> was all contained within that function so I had to re-implement it.

If you can break out exactly what you need, and make that inline
or otherwise available via the correct header, I'm sure it would
have a good chance of being merged.

Keep in mind that you shouldn't introduce an inefficiency to
follow_page, however if that is not possible you could simply
duplicate what you need in a seperate function in mm/memory.c and
use that - better to do it once there than a lot of times in
random places.

--
SUSE Labs, Novell Inc.

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