Re: [PATCH 1/2] vfs: free vfsmount through rcu work from kern_unmount

[Al Viro]

On Fri, Feb 18, 2022 at 01:31:13PM -0500, Rik van Riel wrote:

>  struct super_block;
>  struct vfsmount;
> @@ -73,6 +74,7 @@ struct vfsmount {
>  	struct super_block *mnt_sb;	/* pointer to superblock */
>  	int mnt_flags;
>  	struct user_namespace *mnt_userns;
> +	struct rcu_work free_rwork;
>  } __randomize_layout;

Wait, what?  First of all, that has no business being in vfsmount -
everything that deeply internal belongs in struct mount, not in
its public part.  Moreover, there's already mount->mnt_rcu, so what's
the point duplicating that?