Merge branch 'pm-tools'

[linux-block.git] / mm / shrinker_debug.c

diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c
index 3ab53fad8876ea3f163778c257de5f26a5cb91ed..12ea5486a3e959e299217fc6c1dcef634ae9a291 100644 (file)
--- a/mm/shrinker_debug.c
+++ b/mm/shrinker_debug.c
@@ -6,8 +6,10 @@
 #include <linux/shrinker.h>
 #include <linux/memcontrol.h>
 
+#include "internal.h"
+
 /* defined in vmscan.c */
-extern struct rw_semaphore shrinker_rwsem;
+extern struct mutex shrinker_mutex;
 extern struct list_head shrinker_list;
 
 static DEFINE_IDA(shrinker_debugfs_ida);
@@ -49,17 +51,12 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
        struct mem_cgroup *memcg;
        unsigned long total;
        bool memcg_aware;
-       int ret, nid;
+       int ret = 0, nid;
 
        count_per_node = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
        if (!count_per_node)
                return -ENOMEM;
 
-       ret = down_read_killable(&shrinker_rwsem);
-       if (ret) {
-               kfree(count_per_node);
-               return ret;
-       }
        rcu_read_lock();
 
        memcg_aware = shrinker->flags & SHRINKER_MEMCG_AWARE;
@@ -92,7 +89,6 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
        } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
 
        rcu_read_unlock();
-       up_read(&shrinker_rwsem);
 
        kfree(count_per_node);
        return ret;
@@ -117,7 +113,6 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
        struct mem_cgroup *memcg = NULL;
        int nid;
        char kbuf[72];
-       ssize_t ret;
 
        read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1);
        if (copy_from_user(kbuf, buf, read_len))
@@ -146,12 +141,6 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
                return -EINVAL;
        }
 
-       ret = down_read_killable(&shrinker_rwsem);
-       if (ret) {
-               mem_cgroup_put(memcg);
-               return ret;
-       }
-
        sc.nid = nid;
        sc.memcg = memcg;
        sc.nr_to_scan = nr_to_scan;
@@ -159,7 +148,6 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
 
        shrinker->scan_objects(shrinker, &sc);
 
-       up_read(&shrinker_rwsem);
        mem_cgroup_put(memcg);
 
        return size;
@@ -177,7 +165,7 @@ int shrinker_debugfs_add(struct shrinker *shrinker)
        char buf[128];
        int id;
 
-       lockdep_assert_held(&shrinker_rwsem);
+       lockdep_assert_held(&shrinker_mutex);
 
        /* debugfs isn't initialized yet, add debugfs entries later. */
        if (!shrinker_debugfs_root)
@@ -220,7 +208,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...)
        if (!new)
                return -ENOMEM;
 
-       down_write(&shrinker_rwsem);
+       mutex_lock(&shrinker_mutex);
 
        old = shrinker->name;
        shrinker->name = new;
@@ -238,7 +226,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...)
                        shrinker->debugfs_entry = entry;
        }
 
-       up_write(&shrinker_rwsem);
+       mutex_unlock(&shrinker_mutex);
 
        kfree_const(old);
 
@@ -251,10 +239,7 @@ struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker,
 {
        struct dentry *entry = shrinker->debugfs_entry;
 
-       lockdep_assert_held(&shrinker_rwsem);
-
-       kfree_const(shrinker->name);
-       shrinker->name = NULL;
+       lockdep_assert_held(&shrinker_mutex);
 
        *debugfs_id = entry ? shrinker->debugfs_id : -1;
        shrinker->debugfs_entry = NULL;
@@ -280,14 +265,14 @@ static int __init shrinker_debugfs_init(void)
        shrinker_debugfs_root = dentry;
 
        /* Create debugfs entries for shrinkers registered at boot */
-       down_write(&shrinker_rwsem);
+       mutex_lock(&shrinker_mutex);
        list_for_each_entry(shrinker, &shrinker_list, list)
                if (!shrinker->debugfs_entry) {
                        ret = shrinker_debugfs_add(shrinker);
                        if (ret)
                                break;
                }
-       up_write(&shrinker_rwsem);
+       mutex_unlock(&shrinker_mutex);
 
        return ret;
 }