[PATCH 2/3] Add NOPFN_REFAULT result from vm_ops->nopfn()

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

Add a NOPFN_REFAULT return code for vm_ops->nopfn() equivalent
to NOPAGE_REFAULT for vmops->nopage() indicating that the handler
requests a re-execution of the faulting instruction

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

 include/linux/mm.h |    1 +
 mm/memory.c        |    6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

Index: linux-cell/include/linux/mm.h
===================================================================
--- linux-cell.orig/include/linux/mm.h	2007-02-06 14:40:45.000000000 +1100
+++ linux-cell/include/linux/mm.h	2007-02-06 14:40:52.000000000 +1100
@@ -637,6 +637,7 @@ static inline int page_mapped(struct pag
  */
 #define NOPFN_SIGBUS	((unsigned long) -1)
 #define NOPFN_OOM	((unsigned long) -2)
+#define NOPFN_REFAULT	((unsigned long) -3)
 
 /*
  * Different kinds of faults, as returned by handle_mm_fault().
Index: linux-cell/mm/memory.c
===================================================================
--- linux-cell.orig/mm/memory.c	2007-02-06 14:41:10.000000000 +1100
+++ linux-cell/mm/memory.c	2007-02-06 14:41:45.000000000 +1100
@@ -2357,10 +2357,12 @@ static noinline int do_no_pfn(struct mm_
 	BUG_ON(is_cow_mapping(vma->vm_flags));
 
 	pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK);
-	if (pfn == NOPFN_OOM)
+	if (unlikely(pfn == NOPFN_OOM))
 		return VM_FAULT_OOM;
-	if (pfn == NOPFN_SIGBUS)
+	else if (unlikely(pfn == NOPFN_SIGBUS))
 		return VM_FAULT_SIGBUS;
+	else if (unlikely(pfn == NOPFN_REFAULT))
+		return VM_FAULT_MINOR;
 
 	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);