mm/workingset: do not protect workingset_shadow_nodes with irq off

workingset_shadow_nodes is protected by local_irq_disable(). Some users
use spin_lock_irq().
Replace the irq/on with a local_lock(). Rename workingset_shadow_nodes
so I catch users of it which will be introduced later.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>

3 files changed, 25 insertions, 16 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 37beab98b416..9159e0454fba 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -168,7 +168,9 @@ static void page_cache_tree_delete(struct address_space *mapping,
 	if (!workingset_node_pages(node) &&
 	    list_empty(&node->private_list)) {
 		node->private_data = mapping;
-		list_lru_add(&workingset_shadow_nodes, &node->private_list);
+		local_lock(workingset_shadow_lock);
+		list_lru_add(&__workingset_shadow_nodes, &node->private_list);
+		local_unlock(workingset_shadow_lock);
 	}
 }
 
@@ -535,9 +537,12 @@ static int page_cache_tree_insert(struct address_space *mapping,
 		 * node->private_list is protected by
 		 * mapping->tree_lock.
 		 */
-		if (!list_empty(&node->private_list))
-			list_lru_del(&workingset_shadow_nodes,
+		if (!list_empty(&node->private_list)) {
+			local_lock(workingset_shadow_lock);
+			list_lru_del(&__workingset_shadow_nodes,
 				     &node->private_list);
+			local_unlock(workingset_shadow_lock);
+		}
 	}
 	return 0;
 }
diff --git a/mm/truncate.c b/mm/truncate.c
index f1e4d6052369..a06369d67fa4 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -56,8 +56,11 @@ static void clear_exceptional_entry(struct address_space *mapping,
 	 * protected by mapping->tree_lock.
 	 */
 	if (!workingset_node_shadows(node) &&
-	    !list_empty(&node->private_list))
-		list_lru_del(&workingset_shadow_nodes, &node->private_list);
+	    !list_empty(&node->private_list)) {
+		local_lock(workingset_shadow_lock);
+		list_lru_del(&__workingset_shadow_nodes, &node->private_list);
+		local_unlock(workingset_shadow_lock);
+	}
 	__radix_tree_delete_node(&mapping->page_tree, node);
 unlock:
 	spin_unlock_irq(&mapping->tree_lock);
diff --git a/mm/workingset.c b/mm/workingset.c
index f7216fa7da27..0decb9ca8db8 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -264,7 +264,8 @@ void workingset_activation(struct page *page)
  * point where they would still be useful.
  */
 
-struct list_lru workingset_shadow_nodes;
+struct list_lru __workingset_shadow_nodes;
+DEFINE_LOCAL_IRQ_LOCK(workingset_shadow_lock);
 
 static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 					struct shrink_control *sc)
@@ -274,9 +275,9 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 	unsigned long pages;
 
 	/* list_lru lock nests inside IRQ-safe mapping->tree_lock */
-	local_irq_disable();
-	shadow_nodes = list_lru_count_node(&workingset_shadow_nodes, sc->nid);
-	local_irq_enable();
+	local_lock_irq(workingset_shadow_lock);
+	shadow_nodes = list_lru_count_node(&__workingset_shadow_nodes, sc->nid);
+	local_unlock_irq(workingset_shadow_lock);
 
 	pages = node_present_pages(sc->nid);
 	/*
@@ -362,9 +363,9 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 	spin_unlock(&mapping->tree_lock);
 	ret = LRU_REMOVED_RETRY;
 out:
-	local_irq_enable();
+	local_unlock_irq(workingset_shadow_lock);
 	cond_resched();
-	local_irq_disable();
+	local_lock_irq(workingset_shadow_lock);
 	spin_lock(lru_lock);
 	return ret;
 }
@@ -375,10 +376,10 @@ static unsigned long scan_shadow_nodes(struct shrinker *shrinker,
 	unsigned long ret;
 
 	/* list_lru lock nests inside IRQ-safe mapping->tree_lock */
-	local_irq_disable();
-	ret =  list_lru_walk_node(&workingset_shadow_nodes, sc->nid,
+	local_lock_irq(workingset_shadow_lock);
+	ret =  list_lru_walk_node(&__workingset_shadow_nodes, sc->nid,
 				  shadow_lru_isolate, NULL, &sc->nr_to_scan);
-	local_irq_enable();
+	local_unlock_irq(workingset_shadow_lock);
 	return ret;
 }
 
@@ -399,7 +400,7 @@ static int __init workingset_init(void)
 {
 	int ret;
 
-	ret = list_lru_init_key(&workingset_shadow_nodes, &shadow_nodes_key);
+	ret = list_lru_init_key(&__workingset_shadow_nodes, &shadow_nodes_key);
 	if (ret)
 		goto err;
 	ret = register_shrinker(&workingset_shadow_shrinker);
@@ -407,7 +408,7 @@ static int __init workingset_init(void)
 		goto err_list_lru;
 	return 0;
 err_list_lru:
-	list_lru_destroy(&workingset_shadow_nodes);
+	list_lru_destroy(&__workingset_shadow_nodes);
 err:
 	return ret;
 }