binderfs: rework binderfs_fill_super()

Al pointed out that on binderfs_fill_super() error
deactivate_locked_super() will call binderfs_kill_super() so all of the
freeing and putting we currently do in binderfs_fill_super() is unnecessary
and buggy. Let's simply return errors and let binderfs_fill_super() take
care of cleaning up on error.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christian Brauner <christian@brauner.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 11 insertions, 30 deletions

diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index e73f9dbee099..89a2ee1a02f6 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -461,12 +461,9 @@ static const struct inode_operations binderfs_dir_inode_operations = {
 
 static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
 {
+        int ret;
         struct binderfs_info *info;
-        int ret = -ENOMEM;
         struct inode *inode = NULL;
-        struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
-
-        get_ipc_ns(ipc_ns);
 
         sb->s_blocksize = PAGE_SIZE;
         sb->s_blocksize_bits = PAGE_SHIFT;
@@ -488,15 +485,17 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
         sb->s_op = &binderfs_super_ops;
         sb->s_time_gran = 1;
 
-        info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL);
-        if (!info)
-                goto err_without_dentry;
+        sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL);
+        if (!sb->s_fs_info)
+                return -ENOMEM;
+        info = sb->s_fs_info;
+
+        info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
 
         ret = binderfs_parse_mount_opts(data, &info->mount_opts);
         if (ret)
-                goto err_without_dentry;
+                return ret;
 
-        info->ipc_ns = ipc_ns;
         info->root_gid = make_kgid(sb->s_user_ns, 0);
         if (!gid_valid(info->root_gid))
                 info->root_gid = GLOBAL_ROOT_GID;
@@ -504,12 +503,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
         if (!uid_valid(info->root_uid))
                 info->root_uid = GLOBAL_ROOT_UID;
 
-        sb->s_fs_info = info;
-
-        ret = -ENOMEM;
         inode = new_inode(sb);
         if (!inode)
-                goto err_without_dentry;
+                return -ENOMEM;
 
         inode->i_ino = FIRST_INODE;
         inode->i_fop = &simple_dir_operations;
@@ -520,24 +516,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
 
         sb->s_root = d_make_root(inode);
         if (!sb->s_root)
-                goto err_without_dentry;
-
-        ret = binderfs_binder_ctl_create(sb);
-        if (ret)
-                goto err_with_dentry;
-
-        return 0;
-
-err_with_dentry:
-        dput(sb->s_root);
-        sb->s_root = NULL;
-
-err_without_dentry:
-        put_ipc_ns(ipc_ns);
-        iput(inode);
-        kfree(info);
+                return -ENOMEM;
 
-        return ret;
+        return binderfs_binder_ctl_create(sb);
 }
 
 static struct dentry *binderfs_mount(struct file_system_type *fs_type,