1 files changed, 13 insertions, 14 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 878808c..954032b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -283,6 +283,11 @@ mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
 	return &mem->info.nodeinfo[nid]->zoneinfo[zid];
 }
 
+struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
+{
+	return &mem->css;
+}
+
 static struct mem_cgroup_per_zone *
 page_cgroup_zoneinfo(struct page_cgroup *pc)
 {
@@ -1536,25 +1541,22 @@ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
 	return container_of(css, struct mem_cgroup, css);
 }
 
-static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
+struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
 {
-	struct mem_cgroup *mem;
+	struct mem_cgroup *mem = NULL;
 	struct page_cgroup *pc;
 	unsigned short id;
 	swp_entry_t ent;
 
 	VM_BUG_ON(!PageLocked(page));
 
-	if (!PageSwapCache(page))
-		return NULL;
-
 	pc = lookup_page_cgroup(page);
 	lock_page_cgroup(pc);
 	if (PageCgroupUsed(pc)) {
 		mem = pc->mem_cgroup;
 		if (mem && !css_tryget(&mem->css))
 			mem = NULL;
-	} else {
+	} else if (PageSwapCache(page)) {
 		ent.val = page_private(page);
 		id = lookup_swap_cgroup(ent);
 		rcu_read_lock();
@@ -1874,7 +1876,7 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
 	 */
 	if (!PageSwapCache(page))
 		goto charge_cur_mm;
-	mem = try_get_mem_cgroup_from_swapcache(page);
+	mem = try_get_mem_cgroup_from_page(page);
 	if (!mem)
 		goto charge_cur_mm;
 	*ptr = mem;
@@ -2584,7 +2586,7 @@ static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
 	if (free_all)
 		goto try_to_free;
 move_account:
-	while (mem->res.usage > 0) {
+	do {
 		ret = -EBUSY;
 		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
 			goto out;
@@ -2612,8 +2614,8 @@ move_account:
 		if (ret == -ENOMEM)
 			goto try_to_free;
 		cond_resched();
-	}
-	ret = 0;
+	/* "ret" should also be checked to ensure all lists are empty. */
+	} while (mem->res.usage > 0 || ret);
 out:
 	css_put(&mem->css);
 	return ret;
@@ -2646,10 +2648,7 @@ try_to_free:
 	}
 	lru_add_drain();
 	/* try move_account...there may be some *locked* pages. */
-	if (mem->res.usage)
-		goto move_account;
-	ret = 0;
-	goto out;
+	goto move_account;
 }
 
 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)