kernfs: use idr instead of ida to manage inode number

kernfs uses ida to manage inode number. The problem is we can't get
kernfs_node from inode number with ida. Switching to use idr, next patch
will add an API to get kernfs_node from inode number.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 12 insertions, 5 deletions

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index db5900aaa55a..8ad7a17895fe 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -21,6 +21,7 @@
 DEFINE_MUTEX(kernfs_mutex);
 static DEFINE_SPINLOCK(kernfs_rename_lock);     /* kn->parent and ->name */
 static char kernfs_pr_cont_buf[PATH_MAX];       /* protected by rename_lock */
+static DEFINE_SPINLOCK(kernfs_idr_lock);        /* root->ino_idr */
 
 #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
 
@@ -533,7 +534,9 @@ void kernfs_put(struct kernfs_node *kn)
                 simple_xattrs_free(&kn->iattr->xattrs);
         }
         kfree(kn->iattr);
-        ida_simple_remove(&root->ino_ida, kn->ino);
+        spin_lock(&kernfs_idr_lock);
+        idr_remove(&root->ino_idr, kn->ino);
+        spin_unlock(&kernfs_idr_lock);
         kmem_cache_free(kernfs_node_cache, kn);
 
         kn = parent;
@@ -542,7 +545,7 @@ void kernfs_put(struct kernfs_node *kn)
                         goto repeat;
         } else {
                 /* just released the root kn, free @root too */
-                ida_destroy(&root->ino_ida);
+                idr_destroy(&root->ino_idr);
                 kfree(root);
         }
 }
@@ -630,7 +633,11 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
         if (!kn)
                 goto err_out1;
 
-        ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
+        idr_preload(GFP_KERNEL);
+        spin_lock(&kernfs_idr_lock);
+        ret = idr_alloc(&root->ino_idr, kn, 1, 0, GFP_ATOMIC);
+        spin_unlock(&kernfs_idr_lock);
+        idr_preload_end();
         if (ret < 0)
                 goto err_out2;
         kn->ino = ret;
@@ -875,13 +882,13 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
         if (!root)
                 return ERR_PTR(-ENOMEM);
 
-        ida_init(&root->ino_ida);
+        idr_init(&root->ino_idr);
         INIT_LIST_HEAD(&root->supers);
 
         kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
                                KERNFS_DIR);
         if (!kn) {
-                ida_destroy(&root->ino_ida);
+                idr_destroy(&root->ino_idr);
                 kfree(root);
                 return ERR_PTR(-ENOMEM);
         }