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>

diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index e73f9db..89a2ee1 100644 (file)
--- 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,