memcg: fix oops on NULL lru list

[linux-2.6-omap-h63xx.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f72067094e05f3fc43534995cfd05f6562d4ac8f..8b9f6cae938e98090a8850ba31a8aaf24cc1a1c7 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -623,13 +623,13 @@ retry:
                goto retry;
        }
        page_assign_page_cgroup(page, pc);
-       unlock_page_cgroup(page);
 
        mz = page_cgroup_zoneinfo(pc);
        spin_lock_irqsave(&mz->lru_lock, flags);
        __mem_cgroup_add_list(pc);
        spin_unlock_irqrestore(&mz->lru_lock, flags);
 
+       unlock_page_cgroup(page);
 done:
        return 0;
 out:
@@ -677,14 +677,14 @@ void mem_cgroup_uncharge_page(struct page *page)
        VM_BUG_ON(pc->ref_cnt <= 0);
 
        if (--(pc->ref_cnt) == 0) {
-               page_assign_page_cgroup(page, NULL);
-               unlock_page_cgroup(page);
-
                mz = page_cgroup_zoneinfo(pc);
                spin_lock_irqsave(&mz->lru_lock, flags);
                __mem_cgroup_remove_list(pc);
                spin_unlock_irqrestore(&mz->lru_lock, flags);
 
+               page_assign_page_cgroup(page, NULL);
+               unlock_page_cgroup(page);
+
                mem = pc->mem_cgroup;
                res_counter_uncharge(&mem->res, PAGE_SIZE);
                css_put(&mem->css);
@@ -736,23 +736,24 @@ void mem_cgroup_page_migration(struct page *page, struct page *newpage)
                return;
        }
 
-       page_assign_page_cgroup(page, NULL);
-       unlock_page_cgroup(page);
-
        mz = page_cgroup_zoneinfo(pc);
        spin_lock_irqsave(&mz->lru_lock, flags);
        __mem_cgroup_remove_list(pc);
        spin_unlock_irqrestore(&mz->lru_lock, flags);
 
+       page_assign_page_cgroup(page, NULL);
+       unlock_page_cgroup(page);
+
        pc->page = newpage;
        lock_page_cgroup(newpage);
        page_assign_page_cgroup(newpage, pc);
-       unlock_page_cgroup(newpage);
 
        mz = page_cgroup_zoneinfo(pc);
        spin_lock_irqsave(&mz->lru_lock, flags);
        __mem_cgroup_add_list(pc);
        spin_unlock_irqrestore(&mz->lru_lock, flags);
+
+       unlock_page_cgroup(newpage);
 }
 
 /*