On Sat, 24 Aug 2024, Mike Snitzer wrote:
>
> Also, expose localio's required nfsd symbols to NFS client:
> - Cache nfsd_open_local_fh symbol (defined in next commit) and other
> required nfsd symbols in a globally accessible 'nfs_to'
> nfs_to_nfsd_t struct.
I'm not thrilled with the mechanism for getting these symbols.
I'd rather nfsd passed the symbols to nfs_uuid_is_local(), and it stored
them somewhere that nfs can see them. No need for reference counting
etc. If nfs/localio holds an auth_domain, then it implicitly holds a
reference to the nfsd module and the functions cannot disappear.
I would created an 'nfs_localio_operations' structure which is defined
in nfsd as a constant.
The address of this is passed to nfs_uud_is_local() and that address
is stored in nfs_to if it doesn't already have the correct value.
So no need for symbol_request() or symbol_put().
> +
> +DEFINE_MUTEX(nfs_uuid_mutex);
This doesn't need to be a mutex - a spinlock is sufficient.
> +
> +bool nfs_uuid_is_local(const uuid_t *uuid, struct net *net, struct auth_domain *dom)
> +{
> + bool is_local = false;
> + nfs_uuid_t *nfs_uuid;
> +
> + rcu_read_lock();
> + nfs_uuid = nfs_uuid_lookup(uuid);
> + if (nfs_uuid) {
> + is_local = true;
> + nfs_uuid->net = net;
It looks odd that you don't take a reference to the net.
It is probably correct but a comment explaining why would help.
Is it that the dom implies a reference to the net?
> + kref_get(&dom->ref);
> + nfs_uuid->dom = dom;
> + }
> + rcu_read_unlock();
> +
> + return is_local;
> +}
> +EXPORT_SYMBOL_GPL(nfs_uuid_is_local);
Thanks,
NeilBrown
