diff mbox series

[v7,1/5] NFSD: convert write_threads to netlink command

Message ID d822328a8bdf7c796f6722139accba672466703a.1712853394.git.lorenzo@kernel.org (mailing list archive)
State Superseded
Headers show
Series convert write_threads, write_version and write_ports to netlink commands | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; GEN HAS DIFF 2 files changed, 616 insertions(+);
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 942 this patch: 942
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 7 maintainers not CCed: pabeni@redhat.com trond.myklebust@hammerspace.com anna@kernel.org edumazet@google.com Dai.Ngo@oracle.com kolga@netapp.com tom@talpey.com
netdev/build_clang success Errors and warnings before: 953 this patch: 953
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 953 this patch: 953
netdev/checkpatch warning WARNING: line length of 95 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc fail Errors and warnings before: 4 this patch: 6
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-04-12--06-00 (tests: 962)

Commit Message

Lorenzo Bianconi April 11, 2024, 4:47 p.m. UTC 
Introduce write_threads netlink command similar to the one available
through the procfs.

Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 Documentation/netlink/specs/nfsd.yaml | 23 ++++++++++
 fs/nfsd/netlink.c                     | 17 ++++++++
 fs/nfsd/netlink.h                     |  2 +
 fs/nfsd/nfsctl.c                      | 60 +++++++++++++++++++++++++++
 include/uapi/linux/nfsd_netlink.h     |  9 ++++
 5 files changed, 111 insertions(+)

Comments

Jeff Layton April 12, 2024, 1:21 p.m. UTC | #1 
On Thu, 2024-04-11 at 18:47 +0200, Lorenzo Bianconi wrote:
> Introduce write_threads netlink command similar to the one available
> through the procfs.
> 
> Tested-by: Jeff Layton <jlayton@kernel.org>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  Documentation/netlink/specs/nfsd.yaml | 23 ++++++++++
>  fs/nfsd/netlink.c                     | 17 ++++++++
>  fs/nfsd/netlink.h                     |  2 +
>  fs/nfsd/nfsctl.c                      | 60 +++++++++++++++++++++++++++
>  include/uapi/linux/nfsd_netlink.h     |  9 ++++
>  5 files changed, 111 insertions(+)
> 
> diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
> index 05acc73e2e33..c92e1425d316 100644
> --- a/Documentation/netlink/specs/nfsd.yaml
> +++ b/Documentation/netlink/specs/nfsd.yaml
> @@ -62,6 +62,12 @@ attribute-sets:
>          name: compound-ops
>          type: u32
>          multi-attr: true
> +  -
> +    name: server-worker
> +    attributes:
> +      -
> +        name: threads
> +        type: u32
>  
>  operations:
>    list:
> @@ -87,3 +93,20 @@ 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

There's only one thing I think we're missing to get feature parity with
rpc.nfsd, and that's the ability to set the lease-time and grace-time
when starting the server.

I think the simplest thing to do would be to just add 2 optional int
parameters to the threads-set command. They only matter once you're
starting the server anyway. I'll see about spinning up a patch, but let
me know if you see problems with that approach.

> +    -
> +      name: threads-get
> +      doc: get the number of running threads
> +      attribute-set: server-worker
> +      do:
> +        reply:
> +          attributes:
> +            - threads
> diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
> index 0e1d635ec5f9..1a59a8e6c7e2 100644
> --- a/fs/nfsd/netlink.c
> +++ b/fs/nfsd/netlink.c
> @@ -10,6 +10,11 @@
>  
>  #include <uapi/linux/nfsd_netlink.h>
>  
> +/* NFSD_CMD_THREADS_SET - do */
> +static const struct nla_policy nfsd_threads_set_nl_policy[NFSD_A_SERVER_WORKER_THREADS + 1] = {
> +	[NFSD_A_SERVER_WORKER_THREADS] = { .type = NLA_U32, },
> +};
> +
>  /* Ops table for nfsd */
>  static const struct genl_split_ops nfsd_nl_ops[] = {
>  	{
> @@ -19,6 +24,18 @@ static const struct genl_split_ops nfsd_nl_ops[] = {
>  		.done	= nfsd_nl_rpc_status_get_done,
>  		.flags	= GENL_CMD_CAP_DUMP,
>  	},
> +	{
> +		.cmd		= NFSD_CMD_THREADS_SET,
> +		.doit		= nfsd_nl_threads_set_doit,
> +		.policy		= nfsd_threads_set_nl_policy,
> +		.maxattr	= NFSD_A_SERVER_WORKER_THREADS,
> +		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> +	},
> +	{
> +		.cmd	= NFSD_CMD_THREADS_GET,
> +		.doit	= nfsd_nl_threads_get_doit,
> +		.flags	= GENL_CMD_CAP_DO,
> +	},
>  };
>  
>  struct genl_family nfsd_nl_family __ro_after_init = {
> 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);
>  
>  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);
>  
>  extern struct genl_family nfsd_nl_family;
>  
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index 93c87587e646..71608744e67f 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1651,6 +1651,66 @@ int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
>  	return 0;
>  }
>  
> +/**
> + * 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)
> +{
> +	u32 nthreads;
> +	int ret;
> +
> +	if (GENL_REQ_ATTR_CHECK(info, NFSD_A_SERVER_WORKER_THREADS))
> +		return -EINVAL;
> +
> +	nthreads = nla_get_u32(info->attrs[NFSD_A_SERVER_WORKER_THREADS]);
> +	ret = nfsd_svc(nthreads,
> +		       genl_info_net(info), get_current_cred());
> +
> +	return ret == nthreads ? 0 : -EINVAL;
> +}
> +
> +/**
> + * 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)
> +{
> +	void *hdr;
> +	int err;
> +
> +	skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> +	if (!skb)
> +		return -ENOMEM;
> +
> +	hdr = genlmsg_iput(skb, info);
> +	if (!hdr) {
> +		err = -EMSGSIZE;
> +		goto err_free_msg;
> +	}
> +
> +	if (nla_put_u32(skb, NFSD_A_SERVER_WORKER_THREADS,
> +			nfsd_nrthreads(genl_info_net(info)))) {
> +		err = -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_netlink.h
> index 3cd044edee5d..1b6fe1f9ed0e 100644
> --- a/include/uapi/linux/nfsd_netlink.h
> +++ b/include/uapi/linux/nfsd_netlink.h
> @@ -29,8 +29,17 @@ enum {
>  	NFSD_A_RPC_STATUS_MAX = (__NFSD_A_RPC_STATUS_MAX - 1)
>  };
>  
> +enum {
> +	NFSD_A_SERVER_WORKER_THREADS = 1,
> +
> +	__NFSD_A_SERVER_WORKER_MAX,
> +	NFSD_A_SERVER_WORKER_MAX = (__NFSD_A_SERVER_WORKER_MAX - 1)
> +};
> +
>  enum {
>  	NFSD_CMD_RPC_STATUS_GET = 1,
> +	NFSD_CMD_THREADS_SET,
> +	NFSD_CMD_THREADS_GET,
>  
>  	__NFSD_CMD_MAX,
>  	NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)
Lorenzo Bianconi April 12, 2024, 2:24 p.m. UTC | #2 
> On Thu, 2024-04-11 at 18:47 +0200, Lorenzo Bianconi wrote:
> > Introduce write_threads netlink command similar to the one available
> > through the procfs.
> > 
> > Tested-by: Jeff Layton <jlayton@kernel.org>
> > Reviewed-by: Jeff Layton <jlayton@kernel.org>
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >  Documentation/netlink/specs/nfsd.yaml | 23 ++++++++++
> >  fs/nfsd/netlink.c                     | 17 ++++++++
> >  fs/nfsd/netlink.h                     |  2 +
> >  fs/nfsd/nfsctl.c                      | 60 +++++++++++++++++++++++++++
> >  include/uapi/linux/nfsd_netlink.h     |  9 ++++
> >  5 files changed, 111 insertions(+)
> > 
> > diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
> > index 05acc73e2e33..c92e1425d316 100644
> > --- a/Documentation/netlink/specs/nfsd.yaml
> > +++ b/Documentation/netlink/specs/nfsd.yaml
> > @@ -62,6 +62,12 @@ attribute-sets:
> >          name: compound-ops
> >          type: u32
> >          multi-attr: true
> > +  -
> > +    name: server-worker
> > +    attributes:
> > +      -
> > +        name: threads
> > +        type: u32
> >  
> >  operations:
> >    list:
> > @@ -87,3 +93,20 @@ 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
> 
> There's only one thing I think we're missing to get feature parity with
> rpc.nfsd, and that's the ability to set the lease-time and grace-time
> when starting the server.
> 
> I think the simplest thing to do would be to just add 2 optional int
> parameters to the threads-set command. They only matter once you're
> starting the server anyway. I'll see about spinning up a patch, but let
> me know if you see problems with that approach.

ack, I am fine with it, we can squash it in the next revision or send a
follow-up patch.

Regards,
Lorenzo

> 
> > +    -
> > +      name: threads-get
> > +      doc: get the number of running threads
> > +      attribute-set: server-worker
> > +      do:
> > +        reply:
> > +          attributes:
> > +            - threads
> > diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
> > index 0e1d635ec5f9..1a59a8e6c7e2 100644
> > --- a/fs/nfsd/netlink.c
> > +++ b/fs/nfsd/netlink.c
> > @@ -10,6 +10,11 @@
> >  
> >  #include <uapi/linux/nfsd_netlink.h>
> >  
> > +/* NFSD_CMD_THREADS_SET - do */
> > +static const struct nla_policy nfsd_threads_set_nl_policy[NFSD_A_SERVER_WORKER_THREADS + 1] = {
> > +	[NFSD_A_SERVER_WORKER_THREADS] = { .type = NLA_U32, },
> > +};
> > +
> >  /* Ops table for nfsd */
> >  static const struct genl_split_ops nfsd_nl_ops[] = {
> >  	{
> > @@ -19,6 +24,18 @@ static const struct genl_split_ops nfsd_nl_ops[] = {
> >  		.done	= nfsd_nl_rpc_status_get_done,
> >  		.flags	= GENL_CMD_CAP_DUMP,
> >  	},
> > +	{
> > +		.cmd		= NFSD_CMD_THREADS_SET,
> > +		.doit		= nfsd_nl_threads_set_doit,
> > +		.policy		= nfsd_threads_set_nl_policy,
> > +		.maxattr	= NFSD_A_SERVER_WORKER_THREADS,
> > +		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> > +	},
> > +	{
> > +		.cmd	= NFSD_CMD_THREADS_GET,
> > +		.doit	= nfsd_nl_threads_get_doit,
> > +		.flags	= GENL_CMD_CAP_DO,
> > +	},
> >  };
> >  
> >  struct genl_family nfsd_nl_family __ro_after_init = {
> > 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);
> >  
> >  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);
> >  
> >  extern struct genl_family nfsd_nl_family;
> >  
> > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> > index 93c87587e646..71608744e67f 100644
> > --- a/fs/nfsd/nfsctl.c
> > +++ b/fs/nfsd/nfsctl.c
> > @@ -1651,6 +1651,66 @@ int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
> >  	return 0;
> >  }
> >  
> > +/**
> > + * 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)
> > +{
> > +	u32 nthreads;
> > +	int ret;
> > +
> > +	if (GENL_REQ_ATTR_CHECK(info, NFSD_A_SERVER_WORKER_THREADS))
> > +		return -EINVAL;
> > +
> > +	nthreads = nla_get_u32(info->attrs[NFSD_A_SERVER_WORKER_THREADS]);
> > +	ret = nfsd_svc(nthreads,
> > +		       genl_info_net(info), get_current_cred());
> > +
> > +	return ret == nthreads ? 0 : -EINVAL;
> > +}
> > +
> > +/**
> > + * 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)
> > +{
> > +	void *hdr;
> > +	int err;
> > +
> > +	skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> > +	if (!skb)
> > +		return -ENOMEM;
> > +
> > +	hdr = genlmsg_iput(skb, info);
> > +	if (!hdr) {
> > +		err = -EMSGSIZE;
> > +		goto err_free_msg;
> > +	}
> > +
> > +	if (nla_put_u32(skb, NFSD_A_SERVER_WORKER_THREADS,
> > +			nfsd_nrthreads(genl_info_net(info)))) {
> > +		err = -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_netlink.h
> > index 3cd044edee5d..1b6fe1f9ed0e 100644
> > --- a/include/uapi/linux/nfsd_netlink.h
> > +++ b/include/uapi/linux/nfsd_netlink.h
> > @@ -29,8 +29,17 @@ enum {
> >  	NFSD_A_RPC_STATUS_MAX = (__NFSD_A_RPC_STATUS_MAX - 1)
> >  };
> >  
> > +enum {
> > +	NFSD_A_SERVER_WORKER_THREADS = 1,
> > +
> > +	__NFSD_A_SERVER_WORKER_MAX,
> > +	NFSD_A_SERVER_WORKER_MAX = (__NFSD_A_SERVER_WORKER_MAX - 1)
> > +};
> > +
> >  enum {
> >  	NFSD_CMD_RPC_STATUS_GET = 1,
> > +	NFSD_CMD_THREADS_SET,
> > +	NFSD_CMD_THREADS_GET,
> >  
> >  	__NFSD_CMD_MAX,
> >  	NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)
> 
> -- 
> Jeff Layton <jlayton@kernel.org>
>
diff mbox series

Patch

diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
index 05acc73e2e33..c92e1425d316 100644
--- a/Documentation/netlink/specs/nfsd.yaml
+++ b/Documentation/netlink/specs/nfsd.yaml
@@ -62,6 +62,12 @@  attribute-sets:
         name: compound-ops
         type: u32
         multi-attr: true
+  -
+    name: server-worker
+    attributes:
+      -
+        name: threads
+        type: u32
 
 operations:
   list:
@@ -87,3 +93,20 @@  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
+    -
+      name: threads-get
+      doc: get the number of running threads
+      attribute-set: server-worker
+      do:
+        reply:
+          attributes:
+            - threads
diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
index 0e1d635ec5f9..1a59a8e6c7e2 100644
--- a/fs/nfsd/netlink.c
+++ b/fs/nfsd/netlink.c
@@ -10,6 +10,11 @@ 
 
 #include <uapi/linux/nfsd_netlink.h>
 
+/* NFSD_CMD_THREADS_SET - do */
+static const struct nla_policy nfsd_threads_set_nl_policy[NFSD_A_SERVER_WORKER_THREADS + 1] = {
+	[NFSD_A_SERVER_WORKER_THREADS] = { .type = NLA_U32, },
+};
+
 /* Ops table for nfsd */
 static const struct genl_split_ops nfsd_nl_ops[] = {
 	{
@@ -19,6 +24,18 @@  static const struct genl_split_ops nfsd_nl_ops[] = {
 		.done	= nfsd_nl_rpc_status_get_done,
 		.flags	= GENL_CMD_CAP_DUMP,
 	},
+	{
+		.cmd		= NFSD_CMD_THREADS_SET,
+		.doit		= nfsd_nl_threads_set_doit,
+		.policy		= nfsd_threads_set_nl_policy,
+		.maxattr	= NFSD_A_SERVER_WORKER_THREADS,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd	= NFSD_CMD_THREADS_GET,
+		.doit	= nfsd_nl_threads_get_doit,
+		.flags	= GENL_CMD_CAP_DO,
+	},
 };
 
 struct genl_family nfsd_nl_family __ro_after_init = {
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);
 
 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);
 
 extern struct genl_family nfsd_nl_family;
 
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 93c87587e646..71608744e67f 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1651,6 +1651,66 @@  int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
 	return 0;
 }
 
+/**
+ * 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)
+{
+	u32 nthreads;
+	int ret;
+
+	if (GENL_REQ_ATTR_CHECK(info, NFSD_A_SERVER_WORKER_THREADS))
+		return -EINVAL;
+
+	nthreads = nla_get_u32(info->attrs[NFSD_A_SERVER_WORKER_THREADS]);
+	ret = nfsd_svc(nthreads,
+		       genl_info_net(info), get_current_cred());
+
+	return ret == nthreads ? 0 : -EINVAL;
+}
+
+/**
+ * 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)
+{
+	void *hdr;
+	int err;
+
+	skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	hdr = genlmsg_iput(skb, info);
+	if (!hdr) {
+		err = -EMSGSIZE;
+		goto err_free_msg;
+	}
+
+	if (nla_put_u32(skb, NFSD_A_SERVER_WORKER_THREADS,
+			nfsd_nrthreads(genl_info_net(info)))) {
+		err = -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_netlink.h
index 3cd044edee5d..1b6fe1f9ed0e 100644
--- a/include/uapi/linux/nfsd_netlink.h
+++ b/include/uapi/linux/nfsd_netlink.h
@@ -29,8 +29,17 @@  enum {
 	NFSD_A_RPC_STATUS_MAX = (__NFSD_A_RPC_STATUS_MAX - 1)
 };
 
+enum {
+	NFSD_A_SERVER_WORKER_THREADS = 1,
+
+	__NFSD_A_SERVER_WORKER_MAX,
+	NFSD_A_SERVER_WORKER_MAX = (__NFSD_A_SERVER_WORKER_MAX - 1)
+};
+
 enum {
 	NFSD_CMD_RPC_STATUS_GET = 1,
+	NFSD_CMD_THREADS_SET,
+	NFSD_CMD_THREADS_GET,
 
 	__NFSD_CMD_MAX,
 	NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)