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From: Jeff Layton <jlayton@kernel.org>
Date: Thu, 13 Jun 2024 14:34:34 -0400
Subject: [PATCH v3 5/5] nfsd: new netlink ops to get/set server pool_mode
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Message-Id: <20240613-nfsd-next-v3-5-3b51c3c2fc59@kernel.org>
References: <20240613-nfsd-next-v3-0-3b51c3c2fc59@kernel.org>
In-Reply-To: <20240613-nfsd-next-v3-0-3b51c3c2fc59@kernel.org>
To: Chuck Lever <chuck.lever@oracle.com>, Neil Brown <neilb@suse.de>, 
 Olga Kornievskaia <kolga@netapp.com>, Dai Ngo <Dai.Ngo@oracle.com>, 
 Tom Talpey <tom@talpey.com>, "David S. Miller" <davem@davemloft.net>, 
 Eric Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>, 
 Paolo Abeni <pabeni@redhat.com>, Lorenzo Bianconi <lorenzo@kernel.org>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>, 
 Anna Schumaker <anna@kernel.org>, linux-nfs@vger.kernel.org, 
 linux-kernel@vger.kernel.org, netdev@vger.kernel.org, 
 Jeff Layton <jlayton@kernel.org>

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 Documentation/netlink/specs/nfsd.yaml | 27 ++++++++++++++++
 fs/nfsd/netlink.c                     | 17 ++++++++++
 fs/nfsd/netlink.h                     |  2 ++
 fs/nfsd/nfsctl.c                      | 58 +++++++++++++++++++++++++++++++++++
 include/uapi/linux/nfsd_netlink.h     | 10 ++++++
 5 files changed, 114 insertions(+)

diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
index d21234097167..5a98e5a06c68 100644
--- a/Documentation/netlink/specs/nfsd.yaml
+++ b/Documentation/netlink/specs/nfsd.yaml
@@ -115,6 +115,15 @@ attribute-sets:
         type: nest
         nested-attributes: sock
         multi-attr: true
+  -
+    name: pool-mode
+    attributes:
+      -
+        name: mode
+        type: string
+      -
+        name: npools
+        type: u32
 
 operations:
   list:
@@ -197,3 +206,21 @@ operations:
         reply:
           attributes:
             - addr
+    -
+      name: pool-mode-set
+      doc: set the current server pool-mode
+      attribute-set: pool-mode
+      flags: [ admin-perm ]
+      do:
+        request:
+          attributes:
+            - mode
+    -
+      name: pool-mode-get
+      doc: get info about server pool-mode
+      attribute-set: pool-mode
+      do:
+        reply:
+          attributes:
+            - mode
+            - npools
diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
index 62d2586d9902..137701153c9e 100644
--- a/fs/nfsd/netlink.c
+++ b/fs/nfsd/netlink.c
@@ -40,6 +40,11 @@ static const struct nla_policy nfsd_listener_set_nl_policy[NFSD_A_SERVER_SOCK_AD
 	[NFSD_A_SERVER_SOCK_ADDR] = NLA_POLICY_NESTED(nfsd_sock_nl_policy),
 };
 
+/* NFSD_CMD_POOL_MODE_SET - do */
+static const struct nla_policy nfsd_pool_mode_set_nl_policy[NFSD_A_POOL_MODE_MODE + 1] = {
+	[NFSD_A_POOL_MODE_MODE] = { .type = NLA_NUL_STRING, },
+};
+
 /* Ops table for nfsd */
 static const struct genl_split_ops nfsd_nl_ops[] = {
 	{
@@ -85,6 +90,18 @@ static const struct genl_split_ops nfsd_nl_ops[] = {
 		.doit	= nfsd_nl_listener_get_doit,
 		.flags	= GENL_CMD_CAP_DO,
 	},
+	{
+		.cmd		= NFSD_CMD_POOL_MODE_SET,
+		.doit		= nfsd_nl_pool_mode_set_doit,
+		.policy		= nfsd_pool_mode_set_nl_policy,
+		.maxattr	= NFSD_A_POOL_MODE_MODE,
+		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd	= NFSD_CMD_POOL_MODE_GET,
+		.doit	= nfsd_nl_pool_mode_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 e3724637d64d..9459547de04e 100644
--- a/fs/nfsd/netlink.h
+++ b/fs/nfsd/netlink.h
@@ -26,6 +26,8 @@ int nfsd_nl_version_set_doit(struct sk_buff *skb, struct genl_info *info);
 int nfsd_nl_version_get_doit(struct sk_buff *skb, struct genl_info *info);
 int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info);
 int nfsd_nl_listener_get_doit(struct sk_buff *skb, struct genl_info *info);
+int nfsd_nl_pool_mode_set_doit(struct sk_buff *skb, struct genl_info *info);
+int nfsd_nl_pool_mode_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 dde42aad5582..187e9be77b78 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2182,6 +2182,64 @@ int nfsd_nl_listener_get_doit(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+/**
+ * nfsd_nl_pool_mode_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_pool_mode_set_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	const struct nlattr *attr;
+
+	if (GENL_REQ_ATTR_CHECK(info, NFSD_A_POOL_MODE_MODE))
+		return -EINVAL;
+
+	attr = info->attrs[NFSD_A_POOL_MODE_MODE];
+	return sunrpc_set_pool_mode(nla_data(attr));
+}
+
+/**
+ * nfsd_nl_pool_mode_get_doit - get info about pool_mode
+ * @skb: reply buffer
+ * @info: netlink metadata and command arguments
+ *
+ * Return 0 on success or a negative errno.
+ */
+int nfsd_nl_pool_mode_get_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = genl_info_net(info);
+	char buf[16];
+	void *hdr;
+	int err;
+
+	skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	err = -EMSGSIZE;
+	hdr = genlmsg_iput(skb, info);
+	if (!hdr)
+		goto err_free_msg;
+
+	err = -ERANGE;
+	if (sunrpc_get_pool_mode(buf, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
+		goto err_free_msg;
+
+	err = nla_put_string(skb, NFSD_A_POOL_MODE_MODE, buf) ||
+	      nla_put_u32(skb, NFSD_A_POOL_MODE_NPOOLS, nfsd_nrpools(net));
+	if (err)
+		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 24c86dbc7ed5..887cbd12b695 100644
--- a/include/uapi/linux/nfsd_netlink.h
+++ b/include/uapi/linux/nfsd_netlink.h
@@ -70,6 +70,14 @@ enum {
 	NFSD_A_SERVER_SOCK_MAX = (__NFSD_A_SERVER_SOCK_MAX - 1)
 };
 
+enum {
+	NFSD_A_POOL_MODE_MODE = 1,
+	NFSD_A_POOL_MODE_NPOOLS,
+
+	__NFSD_A_POOL_MODE_MAX,
+	NFSD_A_POOL_MODE_MAX = (__NFSD_A_POOL_MODE_MAX - 1)
+};
+
 enum {
 	NFSD_CMD_RPC_STATUS_GET = 1,
 	NFSD_CMD_THREADS_SET,
@@ -78,6 +86,8 @@ enum {
 	NFSD_CMD_VERSION_GET,
 	NFSD_CMD_LISTENER_SET,
 	NFSD_CMD_LISTENER_GET,
+	NFSD_CMD_POOL_MODE_SET,
+	NFSD_CMD_POOL_MODE_GET,
 
 	__NFSD_CMD_MAX,
 	NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)

-- 
2.45.2