powerpc/mm: Lockless get_user_pages_fast() for 64-bit (v3)

Implement lockless get_user_pages_fast for 64-bit powerpc.

Page table existence is guaranteed with RCU, and speculative page references
are used to take a reference to the pages without having a prior existence
guarantee on them.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/asm-powerpc/pgtable-ppc64.h b/include/asm-powerpc/pgtable-ppc64.h
index 5fc78c0be302..74c6f380b805 100644
--- a/include/asm-powerpc/pgtable-ppc64.h
+++ b/include/asm-powerpc/pgtable-ppc64.h
@@ -461,6 +461,8 @@ void pgtable_cache_init(void);
         return pt;
 }
 
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long address);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_PGTABLE_PPC64_H_ */