kernfs: RCU protect kernfs_nodes and avoid kernfs_idr_lock in kernfs_find_and_get_nod...

[linux-2.6-microblaze.git] / fs / kernfs / dir.c

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index bce1d7a..458519e 100644 (file)
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -529,6 +529,20 @@ void kernfs_get(struct kernfs_node *kn)
 }
 EXPORT_SYMBOL_GPL(kernfs_get);
 
+static void kernfs_free_rcu(struct rcu_head *rcu)
+{
+       struct kernfs_node *kn = container_of(rcu, struct kernfs_node, rcu);
+
+       kfree_const(kn->name);
+
+       if (kn->iattr) {
+               simple_xattrs_free(&kn->iattr->xattrs, NULL);
+               kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
+       }
+
+       kmem_cache_free(kernfs_node_cache, kn);
+}
+
 /**
  * kernfs_put - put a reference count on a kernfs_node
  * @kn: the target kernfs_node
@@ -557,16 +571,11 @@ void kernfs_put(struct kernfs_node *kn)
        if (kernfs_type(kn) == KERNFS_LINK)
                kernfs_put(kn->symlink.target_kn);
 
-       kfree_const(kn->name);
-
-       if (kn->iattr) {
-               simple_xattrs_free(&kn->iattr->xattrs, NULL);
-               kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
-       }
        spin_lock(&kernfs_idr_lock);
        idr_remove(&root->ino_idr, (u32)kernfs_ino(kn));
        spin_unlock(&kernfs_idr_lock);
-       kmem_cache_free(kernfs_node_cache, kn);
+
+       call_rcu(&kn->rcu, kernfs_free_rcu);
 
        kn = parent;
        if (kn) {
@@ -575,7 +584,7 @@ void kernfs_put(struct kernfs_node *kn)
        } else {
                /* just released the root kn, free @root too */
                idr_destroy(&root->ino_idr);
-               kfree(root);
+               kfree_rcu(root, rcu);
        }
 }
 EXPORT_SYMBOL_GPL(kernfs_put);
@@ -715,7 +724,7 @@ struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root,
        ino_t ino = kernfs_id_ino(id);
        u32 gen = kernfs_id_gen(id);
 
-       spin_lock(&kernfs_idr_lock);
+       rcu_read_lock();
 
        kn = idr_find(&root->ino_idr, (u32)ino);
        if (!kn)
@@ -739,10 +748,10 @@ struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root,
        if (unlikely(!__kernfs_active(kn) || !atomic_inc_not_zero(&kn->count)))
                goto err_unlock;
 
-       spin_unlock(&kernfs_idr_lock);
+       rcu_read_unlock();
        return kn;
 err_unlock:
-       spin_unlock(&kernfs_idr_lock);
+       rcu_read_unlock();
        return NULL;
 }