static int binderfs_binder_device_create()

in binderfs.c [111:221]

• 92 lines of code
• 11 McCabe index (conditional complexity)

static int binderfs_binder_device_create(struct inode *ref_inode,
					 struct binderfs_device __user *userp,
					 struct binderfs_device *req)
{
	int minor, ret;
	struct dentry *dentry, *root;
	struct binder_device *device;
	char *name = NULL;
	size_t name_len;
	struct inode *inode = NULL;
	struct super_block *sb = ref_inode->i_sb;
	struct binderfs_info *info = sb->s_fs_info;
#if defined(CONFIG_IPC_NS)
	bool use_reserve = (info->ipc_ns == &init_ipc_ns);
#else
	bool use_reserve = true;
#endif

	/* Reserve new minor number for the new device. */
	mutex_lock(&binderfs_minors_mutex);
	if (++info->device_count <= info->mount_opts.max)
		minor = ida_alloc_max(&binderfs_minors,
				      use_reserve ? BINDERFS_MAX_MINOR :
						    BINDERFS_MAX_MINOR_CAPPED,
				      GFP_KERNEL);
	else
		minor = -ENOSPC;
	if (minor < 0) {
		--info->device_count;
		mutex_unlock(&binderfs_minors_mutex);
		return minor;
	}
	mutex_unlock(&binderfs_minors_mutex);

	ret = -ENOMEM;
	device = kzalloc(sizeof(*device), GFP_KERNEL);
	if (!device)
		goto err;

	inode = new_inode(sb);
	if (!inode)
		goto err;

	inode->i_ino = minor + INODE_OFFSET;
	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
	init_special_inode(inode, S_IFCHR | 0600,
			   MKDEV(MAJOR(binderfs_dev), minor));
	inode->i_fop = &binder_fops;
	inode->i_uid = info->root_uid;
	inode->i_gid = info->root_gid;

	req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */
	name_len = strlen(req->name);
	/* Make sure to include terminating NUL byte */
	name = kmemdup(req->name, name_len + 1, GFP_KERNEL);
	if (!name)
		goto err;

	refcount_set(&device->ref, 1);
	device->binderfs_inode = inode;
	device->context.binder_context_mgr_uid = INVALID_UID;
	device->context.name = name;
	device->miscdev.name = name;
	device->miscdev.minor = minor;
	mutex_init(&device->context.context_mgr_node_lock);

	req->major = MAJOR(binderfs_dev);
	req->minor = minor;

	if (userp && copy_to_user(userp, req, sizeof(*req))) {
		ret = -EFAULT;
		goto err;
	}

	root = sb->s_root;
	inode_lock(d_inode(root));

	/* look it up */
	dentry = lookup_one_len(name, root, name_len);
	if (IS_ERR(dentry)) {
		inode_unlock(d_inode(root));
		ret = PTR_ERR(dentry);
		goto err;
	}

	if (d_really_is_positive(dentry)) {
		/* already exists */
		dput(dentry);
		inode_unlock(d_inode(root));
		ret = -EEXIST;
		goto err;
	}

	inode->i_private = device;
	d_instantiate(dentry, inode);
	fsnotify_create(root->d_inode, dentry);
	inode_unlock(d_inode(root));

	return 0;

err:
	kfree(name);
	kfree(device);
	mutex_lock(&binderfs_minors_mutex);
	--info->device_count;
	ida_free(&binderfs_minors, minor);
	mutex_unlock(&binderfs_minors_mutex);
	iput(inode);

	return ret;
}