mm: introduce pte_advance_pfn() and use for pte_next_pfn()

The goal is to be able to advance a PTE by an arbitrary number of PFNs. 
So introduce a new API that takes a nr param.  Define the default
implementation here and allow for architectures to override. 
pte_next_pfn() becomes a wrapper around pte_advance_pfn().

Follow up commits will convert each overriding architecture's
pte_next_pfn() to pte_advance_pfn().

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ryan Roberts <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Borislav Petkov (AMD) <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Morse <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yang Shi <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 6 insertions, 3 deletions

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 231370e1b80f..b7ac8358f2aa 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -212,14 +212,17 @@ static inline int pmd_dirty(pmd_t pmd)
 #define arch_flush_lazy_mmu_mode()	do {} while (0)
 #endif
 
-
 #ifndef pte_next_pfn
-static inline pte_t pte_next_pfn(pte_t pte)
+#ifndef pte_advance_pfn
+static inline pte_t pte_advance_pfn(pte_t pte, unsigned long nr)
 {
-	return __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
+	return __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT));
 }
 #endif
 
+#define pte_next_pfn(pte) pte_advance_pfn(pte, 1)
+#endif
+
 #ifndef set_ptes
 /**
  * set_ptes - Map consecutive pages to a contiguous range of addresses.