[PATCH] lock PTE before updating it in 440/BookE page fault handler

[Paul Mackerras]

Eugene Surovegin writes:

> Fix 44x and BookE page fault handler to correctly lock PTE before 
> trying to pte_update() it, otherwise this PTE might be swapped out 
> after pte_present() check but before pte_uptdate() call, resulting in 
> corrupted PTE. This can happen with enabled preemption and low memory 
> condition.

That gives me this for an ARCH=powerpc 32-bit pmac build:

/home/paulus/kernel/powerpc/arch/powerpc/mm/pgtable_32.c:376: error: conflicting types for 'get_pteptr'
/home/paulus/kernel/powerpc/include/asm-ppc/pgtable.h:841: error: previous declaration of 'get_pteptr' was here

Paul.