Staging: Merge 2.6.37-rc5 into staging-next

This was done to handle a number of conflicts in the batman-adv
and winbond drivers properly.  It also now allows us to fix up the sysfs
attributes properly that were not in the .37 release due to them being
only in this tree at the time.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 46 insertions, 20 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2efa8ea07ff7..7a22b4129211 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -61,7 +61,14 @@ struct mem_cgroup *root_mem_cgroup __read_mostly;
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
 int do_swap_account __read_mostly;
-static int really_do_swap_account __initdata = 1; /* for remember boot option*/
+
+/* for remember boot option*/
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
+static int really_do_swap_account __initdata = 1;
+#else
+static int really_do_swap_account __initdata = 0;
+#endif
+
 #else
 #define do_swap_account		(0)
 #endif
@@ -278,13 +285,14 @@ enum move_type {
 
 /* "mc" and its members are protected by cgroup_mutex */
 static struct move_charge_struct {
-	spinlock_t	  lock; /* for from, to, moving_task */
+	spinlock_t	  lock; /* for from, to */
 	struct mem_cgroup *from;
 	struct mem_cgroup *to;
 	unsigned long precharge;
 	unsigned long moved_charge;
 	unsigned long moved_swap;
 	struct task_struct *moving_task;	/* a task moving charges */
+	struct mm_struct *mm;
 	wait_queue_head_t waitq;		/* a waitq for other context */
 } mc = {
 	.lock = __SPIN_LOCK_UNLOCKED(mc.lock),
@@ -2152,7 +2160,7 @@ static void __mem_cgroup_move_account(struct page_cgroup *pc,
 {
 	VM_BUG_ON(from == to);
 	VM_BUG_ON(PageLRU(pc->page));
-	VM_BUG_ON(!PageCgroupLocked(pc));
+	VM_BUG_ON(!page_is_cgroup_locked(pc));
 	VM_BUG_ON(!PageCgroupUsed(pc));
 	VM_BUG_ON(pc->mem_cgroup != from);
 
@@ -4631,7 +4639,7 @@ static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
 	unsigned long precharge;
 	struct vm_area_struct *vma;
 
-	down_read(&mm->mmap_sem);
+	/* We've already held the mmap_sem */
 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
 		struct mm_walk mem_cgroup_count_precharge_walk = {
 			.pmd_entry = mem_cgroup_count_precharge_pte_range,
@@ -4643,7 +4651,6 @@ static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
 		walk_page_range(vma->vm_start, vma->vm_end,
 					&mem_cgroup_count_precharge_walk);
 	}
-	up_read(&mm->mmap_sem);
 
 	precharge = mc.precharge;
 	mc.precharge = 0;
@@ -4694,11 +4701,16 @@ static void mem_cgroup_clear_mc(void)
 
 		mc.moved_swap = 0;
 	}
+	if (mc.mm) {
+		up_read(&mc.mm->mmap_sem);
+		mmput(mc.mm);
+	}
 	spin_lock(&mc.lock);
 	mc.from = NULL;
 	mc.to = NULL;
-	mc.moving_task = NULL;
 	spin_unlock(&mc.lock);
+	mc.moving_task = NULL;
+	mc.mm = NULL;
 	mem_cgroup_end_move(from);
 	memcg_oom_recover(from);
 	memcg_oom_recover(to);
@@ -4724,12 +4736,21 @@ static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
 			return 0;
 		/* We move charges only when we move a owner of the mm */
 		if (mm->owner == p) {
+			/*
+			 * We do all the move charge works under one mmap_sem to
+			 * avoid deadlock with down_write(&mmap_sem)
+			 * -> try_charge() -> if (mc.moving_task) -> sleep.
+			 */
+			down_read(&mm->mmap_sem);
+
 			VM_BUG_ON(mc.from);
 			VM_BUG_ON(mc.to);
 			VM_BUG_ON(mc.precharge);
 			VM_BUG_ON(mc.moved_charge);
 			VM_BUG_ON(mc.moved_swap);
 			VM_BUG_ON(mc.moving_task);
+			VM_BUG_ON(mc.mm);
+
 			mem_cgroup_start_move(from);
 			spin_lock(&mc.lock);
 			mc.from = from;
@@ -4737,14 +4758,16 @@ static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
 			mc.precharge = 0;
 			mc.moved_charge = 0;
 			mc.moved_swap = 0;
-			mc.moving_task = current;
 			spin_unlock(&mc.lock);
+			mc.moving_task = current;
+			mc.mm = mm;
 
 			ret = mem_cgroup_precharge_mc(mm);
 			if (ret)
 				mem_cgroup_clear_mc();
-		}
-		mmput(mm);
+			/* We call up_read() and mmput() in clear_mc(). */
+		} else
+			mmput(mm);
 	}
 	return ret;
 }
@@ -4832,7 +4855,7 @@ static void mem_cgroup_move_charge(struct mm_struct *mm)
 	struct vm_area_struct *vma;
 
 	lru_add_drain_all();
-	down_read(&mm->mmap_sem);
+	/* We've already held the mmap_sem */
 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
 		int ret;
 		struct mm_walk mem_cgroup_move_charge_walk = {
@@ -4851,7 +4874,6 @@ static void mem_cgroup_move_charge(struct mm_struct *mm)
 			 */
 			break;
 	}
-	up_read(&mm->mmap_sem);
 }
 
 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
@@ -4860,17 +4882,11 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
 				struct task_struct *p,
 				bool threadgroup)
 {
-	struct mm_struct *mm;
-
-	if (!mc.to)
+	if (!mc.mm)
 		/* no need to move charge */
 		return;
 
-	mm = get_task_mm(p);
-	if (mm) {
-		mem_cgroup_move_charge(mm);
-		mmput(mm);
-	}
+	mem_cgroup_move_charge(mc.mm);
 	mem_cgroup_clear_mc();
 }
 #else	/* !CONFIG_MMU */
@@ -4911,10 +4927,20 @@ struct cgroup_subsys mem_cgroup_subsys = {
 };
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static int __init enable_swap_account(char *s)
+{
+	/* consider enabled if no parameter or 1 is given */
+	if (!s || !strcmp(s, "1"))
+		really_do_swap_account = 1;
+	else if (!strcmp(s, "0"))
+		really_do_swap_account = 0;
+	return 1;
+}
+__setup("swapaccount", enable_swap_account);
 
 static int __init disable_swap_account(char *s)
 {
-	really_do_swap_account = 0;
+	enable_swap_account("0");
 	return 1;
 }
 __setup("noswapaccount", disable_swap_account);