HWPOISON: Use bitmask/action code for try_to_unmap behaviour

try_to_unmap currently has multiple modi (migration, munlock, normal unmap)
which are selected by magic flag variables. The logic is not very straight
forward, because each of these flag change multiple behaviours (e.g.
migration turns off aging, not only sets up migration ptes etc.)
Also the different flags interact in magic ways.

A later patch in this series adds another mode to try_to_unmap, so
this becomes quickly unmanageable.

Replace the different flags with a action code (migration, munlock, munmap)
and some additional flags as modifiers (ignore mlock, ignore aging).
This makes the logic more straight forward and allows easier extension
to new behaviours. Change all the caller to declare what they want to
do.

This patch is supposed to be a nop in behaviour. If anyone can prove
it is not that would be a bug.

Cc: Lee.Schermerhorn@hp.com
Cc: npiggin@suse.de

Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 939888f9ddab..e3a0cd3859a9 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -669,7 +669,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
         }
 
         /* Establish migration ptes or remove ptes */
-        try_to_unmap(page, 1);
+        try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
 
         if (!page_mapped(page))
                 rc = move_to_new_page(newpage, page);