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From: Jeff Layton <jlayton@kernel.org>
Date: Thu, 13 Jun 2024 14:34:32 -0400
Subject: [PATCH v3 3/5] nfsd: allow passing in array of thread counts via
 netlink
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Message-Id: <20240613-nfsd-next-v3-3-3b51c3c2fc59@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>

Now that nfsd_svc can handle an array of thread counts, fix up the
netlink threads interface to construct one from the netlink call
and pass it through so we can start a pooled server the same way we
would start a normal one.

Note that any unspecified values in the array are considered zeroes,
so it's possible to shut down a pooled server by passing in a short
array that has only zeros, or even an empty array.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/nfsctl.c | 32 ++++++++++++++++++++------------
 fs/nfsd/nfssvc.c | 12 +++++++++++-
 2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index c0d84a6e5416..dde42aad5582 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1671,7 +1671,7 @@ int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
  */
 int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	int nthreads = 0, count = 0, nrpools, ret = -EOPNOTSUPP, rem;
+	int *nthreads, count = 0, nrpools, i, ret = -EOPNOTSUPP, rem;
 	struct net *net = genl_info_net(info);
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 	const struct nlattr *attr;
@@ -1688,15 +1688,22 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
 
 	mutex_lock(&nfsd_mutex);
 
-	nrpools = nfsd_nrpools(net);
-	if (nrpools && count > nrpools)
-		count = nrpools;
-
-	/* XXX: make this handle non-global pool-modes */
-	if (count > 1)
+	nrpools = max(count, nfsd_nrpools(net));
+	nthreads = kcalloc(nrpools, sizeof(int), GFP_KERNEL);
+	if (!nthreads) {
+		ret = -ENOMEM;
 		goto out_unlock;
+	}
+
+	i = 0;
+	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {
+		if (nla_type(attr) == NFSD_A_SERVER_THREADS) {
+			nthreads[i++] = nla_get_u32(attr);
+			if (i >= nrpools)
+				break;
+		}
+	}
 
-	nthreads = nla_get_u32(info->attrs[NFSD_A_SERVER_THREADS]);
 	if (info->attrs[NFSD_A_SERVER_GRACETIME] ||
 	    info->attrs[NFSD_A_SERVER_LEASETIME] ||
 	    info->attrs[NFSD_A_SERVER_SCOPE]) {
@@ -1730,12 +1737,13 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
 			scope = nla_data(attr);
 	}
 
-	ret = nfsd_svc(1, &nthreads, net, get_current_cred(), scope);
-
+	ret = nfsd_svc(nrpools, nthreads, net, get_current_cred(), scope);
+	if (ret > 0)
+		ret = 0;
 out_unlock:
 	mutex_unlock(&nfsd_mutex);
-
-	return ret == nthreads ? 0 : ret;
+	kfree(nthreads);
+	return ret;
 }
 
 /**
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 2e47fd26c9b4..9edb4f7c4cc2 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -763,8 +763,18 @@ int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 					  &nn->nfsd_serv->sv_pools[i],
 					  nthreads[i]);
 		if (err)
-			break;
+			goto out;
 	}
+
+	/* Anything undefined in array is considered to be 0 */
+	for (i = n; i < nn->nfsd_serv->sv_nrpools; ++i) {
+		err = svc_set_num_threads(nn->nfsd_serv,
+					  &nn->nfsd_serv->sv_pools[i],
+					  0);
+		if (err)
+			goto out;
+	}
+out:
 	return err;
 }
 

-- 
2.45.2