mempolicy: fix get_mempolicy() for relative and static nodes

Discovered while testing other mempolicy changes:

get_mempolicy() does not handle static/relative mode flags correctly.
Return the value that the user specified so that it can be restored
via set_mempolicy() if desired.

Signed-off-by: Lee Schermerhorn <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ravikiran Thirumalai <[email protected]>
Cc: KOSAKI Motohiro <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 6cdfa1df57f6d38dc2b1a7e319670cd288ce5b46..8034abd3a1351700414ad7024c16da56774522fd 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -806,9 +806,13 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 
        err = 0;
        if (nmask) {
-               task_lock(current);
-               get_policy_nodemask(pol, nmask);
-               task_unlock(current);
+               if (mpol_store_user_nodemask(pol)) {
+                       *nmask = pol->w.user_nodemask;
+               } else {
+                       task_lock(current);
+                       get_policy_nodemask(pol, nmask);
+                       task_unlock(current);
+               }
        }
 
  out: