Re: [RFC][PATCH 1/4] mm: arch do_page_fault() vs in_atomic()

[Nick Piggin]

Hi Peter,
This patchset looks pretty nice to me.

Acked-by: Nick Piggin <npiggin@xxxxxxx>

One minor nit:

Peter Zijlstra wrote:
> In light of the recent pagefault and filemap_copy_from_user work I've
> gone through all the arch pagefault handlers to make sure the 
> inc_preempt_count() 'feature' works as expected.
>
> Several sections of code (including the new filemap_copy_from_user) rely
> on the fact that faults do not take locks under increased preempt count.
>
> arch/x86_64 - good
> arch/powerpc - good
> arch/cris - fixed
> arch/i386 - good
> arch/parisc - fixed
> arch/sh - good
> arch/sparc - good
> arch/s390 - good
> arch/m68k - fixed
> arch/ppc - good
> arch/alpha - fixed
> arch/mips - good
> arch/sparc64 - good
> arch/ia64 - good
> arch/arm - fixed
> arch/um - NA

um does have a fault handler (in kernel/trap.c), but it gets the
in_atomic check correct.

Thanks for doing this.

Nick

--
SUSE Labs, Novell Inc.
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