mempolicy: change get_task_policy() to return default_policy rather than NULL

Every caller of get_task_policy() falls back to default_policy if it
returns NULL. Change get_task_policy() to do this.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 18 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index c0c5d388046f..656db97584f0 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -126,22 +126,20 @@ static struct mempolicy preferred_node_policy[MAX_NUMNODES];
 static struct mempolicy *get_task_policy(struct task_struct *p)
 {
         struct mempolicy *pol = p->mempolicy;
+        int node;
 
-        if (!pol) {
-                int node = numa_node_id();
+        if (pol)
+                return pol;
 
-                if (node != NUMA_NO_NODE) {
-                        pol = &preferred_node_policy[node];
-                        /*
-                         * preferred_node_policy is not initialised early in
-                         * boot
-                         */
-                        if (!pol->mode)
-                                pol = NULL;
-                }
+        node = numa_node_id();
+        if (node != NUMA_NO_NODE) {
+                pol = &preferred_node_policy[node];
+                /* preferred_node_policy is not initialised early in boot */
+                if (pol->mode)
+                        return pol;
         }
 
-        return pol;
+        return &default_policy;
 }
 
 static const struct mempolicy_operations {
@@ -1644,14 +1642,14 @@ struct mempolicy *get_vma_policy(struct task_struct *task,
                                 mpol_get(pol);
                 }
         }
-        if (!pol)
-                pol = &default_policy;
+
         return pol;
 }
 
 bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma)
 {
         struct mempolicy *pol = get_task_policy(task);
+
         if (vma) {
                 if (vma->vm_ops && vma->vm_ops->get_policy) {
                         bool ret = false;
@@ -1667,9 +1665,6 @@ bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma)
                 }
         }
 
-        if (!pol)
-                return default_policy.flags & MPOL_F_MOF;
-
         return pol->flags & MPOL_F_MOF;
 }
 
@@ -2077,7 +2072,7 @@ struct page *alloc_pages_current(gfp_t gfp, unsigned order)
         struct page *page;
         unsigned int cpuset_mems_cookie;
 
-        if (!pol || in_interrupt() || (gfp & __GFP_THISNODE))
+        if (in_interrupt() || (gfp & __GFP_THISNODE))
                 pol = &default_policy;
 
 retry_cpuset: