Re: [RFC PATCH 17/20] famfs: Add module stuff

Jonathan Cameron
2024-02-26T13:47:52Z

On Fri, 23 Feb 2024 11:42:01 -0600
John Groves <John@Groves.net> wrote:

> This commit introduces the module init and exit machinery for famfs.
>
> Signed-off-by: John Groves <john@groves.net>
I'd prefer to see this from the start with the functionality of the module
built up as you go + build logic in place. Makes it easy to spot places
where the patches aren't appropriately self constrained.
> ---
> fs/famfs/famfs_inode.c | 44 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
>
> diff --git a/fs/famfs/famfs_inode.c b/fs/famfs/famfs_inode.c
> index ab46ec50b70d..0d659820e8ff 100644
> --- a/fs/famfs/famfs_inode.c
> +++ b/fs/famfs/famfs_inode.c
> @@ -462,4 +462,48 @@ static struct file_system_type famfs_fs_type = {
> .fs_flags = FS_USERNS_MOUNT,
> };
>
> +/*****************************************************************************************
> + * Module stuff

I'd drop these drivers structure comments. They add little beyond
a high possibility of being wrong after the code has evolved a bit.

> + */
> +static struct kobject *famfs_kobj;
> +
> +static int __init init_famfs_fs(void)
> +{
> + int rc;
> +
> +#if defined(CONFIG_DEV_DAX_IOMAP)
> + pr_notice("%s: Your kernel supports famfs on /dev/dax\n", __func__);
> +#else
> + pr_notice("%s: Your kernel does not support famfs on /dev/dax\n", __func__);
> +#endif
> + famfs_kobj = kobject_create_and_add(MODULE_NAME, fs_kobj);
> + if (!famfs_kobj) {
> + pr_warn("Failed to create kobject\n");
> + return -ENOMEM;
> + }
> +
> + rc = sysfs_create_group(famfs_kobj, &famfs_attr_group);
> + if (rc) {
> + kobject_put(famfs_kobj);
> + pr_warn("%s: Failed to create sysfs group\n", __func__);
> + return rc;
> + }
> +
> + return register_filesystem(&famfs_fs_type);

If this fails, do we not leak the kobj and sysfs groups?

> +}
> +
> +static void
> +__exit famfs_exit(void)
> +{
> + sysfs_remove_group(famfs_kobj, &famfs_attr_group);
> + kobject_put(famfs_kobj);
> + unregister_filesystem(&famfs_fs_type);
> + pr_info("%s: unregistered\n", __func__);
> +}
> +
> +
> +fs_initcall(init_famfs_fs);
> +module_exit(famfs_exit);
> +
> +MODULE_AUTHOR("John Groves, Micron Technology");
> MODULE_LICENSE("GPL");