mm/gup: Drop the arch_pte_access_permitted() MMU callback

The only arch that defines it to something meaningful is x86.
But x86 doesn't use the generic GUP_fast() implementation -- the
only place where the callback is called.

Let's drop it.

Signed-off-by: Kirill A. Shutemov <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Aneesh Kumar K . V <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Dann Frazier <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Rik van Riel <[e-mail]>
Cc: Steve Capper <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/powerpc/include/asm/mmu_context.h

···
 	/* by default, allow everything */
 	return true;
 }
-
-static inline bool arch_pte_access_permitted(pte_t pte, bool write)
-{
-	/* by default, allow everything */
-	return true;
-}
 #endif /* __KERNEL__ */
 #endif /* __ASM_POWERPC_MMU_CONTEXT_H */

arch/s390/include/asm/mmu_context.h

···
 	/* by default, allow everything */
 	return true;
 }
-
-static inline bool arch_pte_access_permitted(pte_t pte, bool write)
-{
-	/* by default, allow everything */
-	return true;
-}
 #endif /* __S390_MMU_CONTEXT_H */

arch/um/include/asm/mmu_context.h

···
 	return true;
 }
 
-static inline bool arch_pte_access_permitted(pte_t pte, bool write)
-{
-	/* by default, allow everything */
-	return true;
-}
-
 /*
  * end asm-generic/mm_hooks.h functions
  */

arch/unicore32/include/asm/mmu_context.h

···
 	/* by default, allow everything */
 	return true;
 }
-
-static inline bool arch_pte_access_permitted(pte_t pte, bool write)
-{
-	/* by default, allow everything */
-	return true;
-}
 #endif

arch/x86/include/asm/mmu_context.h

···
 	return __pkru_allows_pkey(vma_pkey(vma), write);
 }
 
-static inline bool arch_pte_access_permitted(pte_t pte, bool write)
-{
-	return __pkru_allows_pkey(pte_flags_pkey(pte_flags(pte)), write);
-}
 #endif /* _ASM_X86_MMU_CONTEXT_H */

include/asm-generic/mm_hooks.h

···
 	/* by default, allow everything */
 	return true;
 }
-
-static inline bool arch_pte_access_permitted(pte_t pte, bool write)
-{
-	/* by default, allow everything */
-	return true;
-}
 #endif	/* _ASM_GENERIC_MM_HOOKS_H */

mm/gup.c

···
 			pte_protnone(pte) || (write && !pte_write(pte)))
 			goto pte_unmap;
 
-		if (!arch_pte_access_permitted(pte, write))
-			goto pte_unmap;
-
 		VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
 		page = pte_page(pte);
 		head = compound_head(page);