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From: "NeilBrown" <neilb@suse.de>
To: "Lorenzo Bianconi" <lorenzo@kernel.org>
Cc: linux-nfs@vger.kernel.org, lorenzo.bianconi@redhat.com,
 chuck.lever@oracle.com, netdev@vger.kernel.org, kuba@kernel.org,
 jlayton@kernel.org
Subject: Re: [PATCH v8 2/6] NFSD: convert write_threads to netlink command
In-reply-to:
 <4ff777ebb8652e31709bd91c3af50693edf86a26.1713209938.git.lorenzo@kernel.org>
References: <cover.1713209938.git.lorenzo@kernel.org>,
 <4ff777ebb8652e31709bd91c3af50693edf86a26.1713209938.git.lorenzo@kernel.org>
Date: Wed, 17 Apr 2024 07:55:19 +1000
Message-id: <171330451967.17212.2388131327788656190@noble.neil.brown.name>

On Tue, 16 Apr 2024, Lorenzo Bianconi wrote:
> Introduce write_threads netlink command similar to the one available
> through the procfs.

I think this should support write_pool_threads too.
i.e.  the number of threads should be an array.  If it is a singleton,
the it does write_threads.   If larger it does write_pool_threads.
I don't think we want to add a separate command later for pool_threads.

NeilBrown


>=20
> Tested-by: Jeff Layton <jlayton@kernel.org>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> Co-developed-by: Jeff Layton <jlayton@kernel.org>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  Documentation/netlink/specs/nfsd.yaml |  33 ++++++++
>  fs/nfsd/netlink.c                     |  19 +++++
>  fs/nfsd/netlink.h                     |   2 +
>  fs/nfsd/nfsctl.c                      | 104 ++++++++++++++++++++++++++
>  include/uapi/linux/nfsd_netlink.h     |  11 +++
>  5 files changed, 169 insertions(+)
>=20
> diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/=
specs/nfsd.yaml
> index 05acc73e2e33..cbe6c5fd6c4d 100644
> --- a/Documentation/netlink/specs/nfsd.yaml
> +++ b/Documentation/netlink/specs/nfsd.yaml
> @@ -62,6 +62,18 @@ attribute-sets:
>          name: compound-ops
>          type: u32
>          multi-attr: true
> +  -
> +    name: server-worker
> +    attributes:
> +      -
> +        name: threads
> +        type: u32
> +      -
> +        name: gracetime
> +        type: u32
> +      -
> +        name: leasetime
> +        type: u32
> =20
>  operations:
>    list:
> @@ -87,3 +99,24 @@ operations:
>              - sport
>              - dport
>              - compound-ops
> +    -
> +      name: threads-set
> +      doc: set the number of running threads
> +      attribute-set: server-worker
> +      flags: [ admin-perm ]
> +      do:
> +        request:
> +          attributes:
> +            - threads
> +            - gracetime
> +            - leasetime
> +    -
> +      name: threads-get
> +      doc: get the number of running threads
> +      attribute-set: server-worker
> +      do:
> +        reply:
> +          attributes:
> +            - threads
> +            - gracetime
> +            - leasetime
> diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
> index 0e1d635ec5f9..20a646af0324 100644
> --- a/fs/nfsd/netlink.c
> +++ b/fs/nfsd/netlink.c
> @@ -10,6 +10,13 @@
> =20
>  #include <uapi/linux/nfsd_netlink.h>
> =20
> +/* NFSD_CMD_THREADS_SET - do */
> +static const struct nla_policy nfsd_threads_set_nl_policy[NFSD_A_SERVER_WO=
RKER_LEASETIME + 1] =3D {
> +	[NFSD_A_SERVER_WORKER_THREADS] =3D { .type =3D NLA_U32, },
> +	[NFSD_A_SERVER_WORKER_GRACETIME] =3D { .type =3D NLA_U32, },
> +	[NFSD_A_SERVER_WORKER_LEASETIME] =3D { .type =3D NLA_U32, },
> +};
> +
>  /* Ops table for nfsd */
>  static const struct genl_split_ops nfsd_nl_ops[] =3D {
>  	{
> @@ -19,6 +26,18 @@ static const struct genl_split_ops nfsd_nl_ops[] =3D {
>  		.done	=3D nfsd_nl_rpc_status_get_done,
>  		.flags	=3D GENL_CMD_CAP_DUMP,
>  	},
> +	{
> +		.cmd		=3D NFSD_CMD_THREADS_SET,
> +		.doit		=3D nfsd_nl_threads_set_doit,
> +		.policy		=3D nfsd_threads_set_nl_policy,
> +		.maxattr	=3D NFSD_A_SERVER_WORKER_LEASETIME,
> +		.flags		=3D GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> +	},
> +	{
> +		.cmd	=3D NFSD_CMD_THREADS_GET,
> +		.doit	=3D nfsd_nl_threads_get_doit,
> +		.flags	=3D GENL_CMD_CAP_DO,
> +	},
>  };
> =20
>  struct genl_family nfsd_nl_family __ro_after_init =3D {
> diff --git a/fs/nfsd/netlink.h b/fs/nfsd/netlink.h
> index d83dd6bdee92..4137fac477e4 100644
> --- a/fs/nfsd/netlink.h
> +++ b/fs/nfsd/netlink.h
> @@ -16,6 +16,8 @@ int nfsd_nl_rpc_status_get_done(struct netlink_callback *=
cb);
> =20
>  int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
>  				  struct netlink_callback *cb);
> +int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info);
> +int nfsd_nl_threads_get_doit(struct sk_buff *skb, struct genl_info *info);
> =20
>  extern struct genl_family nfsd_nl_family;
> =20
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index f2e442d7fe16..38a5df03981b 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1653,6 +1653,110 @@ int nfsd_nl_rpc_status_get_done(struct netlink_call=
back *cb)
>  	return 0;
>  }
> =20
> +/**
> + * nfsd_nl_threads_set_doit - set the number of running threads
> + * @skb: reply buffer
> + * @info: netlink metadata and command arguments
> + *
> + * Return 0 on success or a negative errno.
> + */
> +int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
> +{
> +	struct net *net =3D genl_info_net(info);
> +	struct nfsd_net *nn =3D net_generic(net, nfsd_net_id);
> +	int ret =3D -EBUSY;
> +	u32 nthreads;
> +
> +	if (GENL_REQ_ATTR_CHECK(info, NFSD_A_SERVER_WORKER_THREADS))
> +		return -EINVAL;
> +
> +	nthreads =3D nla_get_u32(info->attrs[NFSD_A_SERVER_WORKER_THREADS]);
> +
> +	mutex_lock(&nfsd_mutex);
> +	if (info->attrs[NFSD_A_SERVER_WORKER_GRACETIME] ||
> +	    info->attrs[NFSD_A_SERVER_WORKER_LEASETIME]) {
> +		const struct nlattr *attr;
> +
> +		if (nn->nfsd_serv && nn->nfsd_serv->sv_nrthreads)
> +			goto out_unlock;
> +
> +		ret =3D -EINVAL;
> +		attr =3D info->attrs[NFSD_A_SERVER_WORKER_GRACETIME];
> +		if (attr) {
> +			u32 gracetime =3D nla_get_u32(attr);
> +
> +			if (gracetime < 10 || gracetime > 3600)
> +				goto out_unlock;
> +
> +			nn->nfsd4_grace =3D gracetime;
> +		}
> +
> +		attr =3D info->attrs[NFSD_A_SERVER_WORKER_LEASETIME];
> +		if (attr) {
> +			u32 leasetime =3D nla_get_u32(attr);
> +
> +			if (leasetime < 10 || leasetime > 3600)
> +				goto out_unlock;
> +
> +			nn->nfsd4_lease =3D leasetime;
> +		}
> +	}
> +
> +	ret =3D nfsd_svc(nthreads, net, get_current_cred());
> +out_unlock:
> +	mutex_unlock(&nfsd_mutex);
> +
> +	return ret =3D=3D nthreads ? 0 : ret;
> +}
> +
> +/**
> + * nfsd_nl_threads_get_doit - get the number of running threads
> + * @skb: reply buffer
> + * @info: netlink metadata and command arguments
> + *
> + * Return 0 on success or a negative errno.
> + */
> +int nfsd_nl_threads_get_doit(struct sk_buff *skb, struct genl_info *info)
> +{
> +	struct net *net =3D genl_info_net(info);
> +	struct nfsd_net *nn =3D net_generic(net, nfsd_net_id);
> +	void *hdr;
> +	int err;
> +
> +	skb =3D genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> +	if (!skb)
> +		return -ENOMEM;
> +
> +	hdr =3D genlmsg_iput(skb, info);
> +	if (!hdr) {
> +		err =3D -EMSGSIZE;
> +		goto err_free_msg;
> +	}
> +
> +	mutex_lock(&nfsd_mutex);
> +	err =3D nla_put_u32(skb, NFSD_A_SERVER_WORKER_GRACETIME,
> +			  nn->nfsd4_grace) ||
> +	      nla_put_u32(skb, NFSD_A_SERVER_WORKER_LEASETIME,
> +			  nn->nfsd4_lease) ||
> +	      nla_put_u32(skb, NFSD_A_SERVER_WORKER_THREADS,
> +			  nn->nfsd_serv ? nn->nfsd_serv->sv_nrthreads : 0);
> +	mutex_unlock(&nfsd_mutex);
> +
> +	if (err) {
> +		err =3D -EINVAL;
> +		goto err_free_msg;
> +	}
> +
> +	genlmsg_end(skb, hdr);
> +
> +	return genlmsg_reply(skb, info);
> +
> +err_free_msg:
> +	nlmsg_free(skb);
> +
> +	return err;
> +}
> +
>  /**
>   * nfsd_net_init - Prepare the nfsd_net portion of a new net namespace
>   * @net: a freshly-created network namespace
> diff --git a/include/uapi/linux/nfsd_netlink.h b/include/uapi/linux/nfsd_ne=
tlink.h
> index 3cd044edee5d..ccc78a5ee650 100644
> --- a/include/uapi/linux/nfsd_netlink.h
> +++ b/include/uapi/linux/nfsd_netlink.h
> @@ -29,8 +29,19 @@ enum {
>  	NFSD_A_RPC_STATUS_MAX =3D (__NFSD_A_RPC_STATUS_MAX - 1)
>  };
> =20
> +enum {
> +	NFSD_A_SERVER_WORKER_THREADS =3D 1,
> +	NFSD_A_SERVER_WORKER_GRACETIME,
> +	NFSD_A_SERVER_WORKER_LEASETIME,
> +
> +	__NFSD_A_SERVER_WORKER_MAX,
> +	NFSD_A_SERVER_WORKER_MAX =3D (__NFSD_A_SERVER_WORKER_MAX - 1)
> +};
> +
>  enum {
>  	NFSD_CMD_RPC_STATUS_GET =3D 1,
> +	NFSD_CMD_THREADS_SET,
> +	NFSD_CMD_THREADS_GET,
> =20
>  	__NFSD_CMD_MAX,
>  	NFSD_CMD_MAX =3D (__NFSD_CMD_MAX - 1)
> --=20
> 2.44.0
>=20
>=20