[PATCH] mm: don't rely on flags coincidence

[Hugh Dickins <hugh.dickins@tiscali.co.uk>]

Indeed FOLL_WRITE matches FAULT_FLAG_WRITE, matches GUP_FLAGS_WRITE,
and it's tempting to devise a set of Grand Unified Paging flags;
but not today.  So until then, let's rely upon the compiler to spot
the coincidence, "rather than have that subtle dependency and a
comment for it" - as you remarked in another context yesterday.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
---

 mm/memory.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- 2.6.30-git20/mm/memory.c	2009-06-23 11:06:25.000000000 +0100
+++ linux/mm/memory.c	2009-06-23 13:07:57.000000000 +0100
@@ -1311,8 +1311,10 @@ int __get_user_pages(struct task_struct
 			while (!(page = follow_page(vma, start, foll_flags))) {
 				int ret;
 
-				/* FOLL_WRITE matches FAULT_FLAG_WRITE! */
-				ret = handle_mm_fault(mm, vma, start, foll_flags & FOLL_WRITE);
+				ret = handle_mm_fault(mm, vma, start,
+					(foll_flags & FOLL_WRITE) ?
+					FAULT_FLAG_WRITE : 0);
+
 				if (ret & VM_FAULT_ERROR) {
 					if (ret & VM_FAULT_OOM)
 						return i ? i : -ENOMEM;

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