Re: linux-next: 1ea0704e (ptep_modify_prot transaction abstraction) breaks no-mmu

[Jeremy Fitzhardinge <jeremy@goop.org>]

Mike Frysinger wrote:
> the functions added to asm-generic/pgtable.h are only used by
> mm/mprotect.c (a MMU-only file), but they were not added inside of the
> CONFIG_MMU ifdef block.  since the functions rely on things inside of
> CONFIG_MMU (the lines just above in pgtable.h), we get build failure
> on all no-mmu setups:
>   CC      init/main.o
> In file included from include/asm/pgtable.h:94,
>                  from include/linux/mm.h:39,
>                  from include/asm/dma.h:39,
>                  from include/linux/bootmem.h:8,
>                  from init/main.c:27:
> include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start':
> include/asm-generic/pgtable.h:210: error: implicit declaration of
> function 'ptep_get_and_clear'
> include/asm-generic/pgtable.h:210: error: incompatible types in return
> make[1]: *** [init/main.o] Error 1
> make: *** [init/main.o] Error 2
> -mike
>   

Uh, OK.  What does mprotect do on a nommu system?  Would it be 
sufficient to move the definitions of __ptep_modify_prot_start/commit 
out of a CONFIG_MMU block, or provide separate no-op versions?

    J