mempolicy: rename mpol_free to mpol_put

This is a change that was requested some time ago by Mel Gorman.  Makes sense
to me, so here it is.

Note: I retain the name "mpol_free_shared_policy()" because it actually does
free the shared_policy, which is NOT a reference counted object.  However, ...

The mempolicy object[s] referenced by the shared_policy are reference counted,
so mpol_put() is used to release the reference held by the shared_policy.  The
mempolicy might not be freed at this time, because some task attached to the
shared object associated with the shared policy may be in the process of
allocating a page based on the mempolicy.  In that case, the task performing
the allocation will hold a reference on the mempolicy, obtained via
mpol_shared_policy_lookup().  The mempolicy will be freed when all tasks
holding such a reference have called mpol_put() for the mempolicy.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 2 insertions, 2 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 97f609f574b1..2a9d98c641ac 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -967,7 +967,7 @@ NORET_TYPE void do_exit(long code)
         proc_exit_connector(tsk);
         exit_notify(tsk, group_dead);
 #ifdef CONFIG_NUMA
-        mpol_free(tsk->mempolicy);
+        mpol_put(tsk->mempolicy);
         tsk->mempolicy = NULL;
 #endif
 #ifdef CONFIG_FUTEX
diff --git a/kernel/fork.c b/kernel/fork.c
index c674aa8d3c31..1a5ae2084574 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1374,7 +1374,7 @@ bad_fork_cleanup_security:
         security_task_free(p);
 bad_fork_cleanup_policy:
 #ifdef CONFIG_NUMA
-        mpol_free(p->mempolicy);
+        mpol_put(p->mempolicy);
 bad_fork_cleanup_cgroup:
 #endif
         cgroup_exit(p, cgroup_callbacks_done);