[PATCH] ipvs: Fix reuse connection if RS weight is 0

[yangxingwu <xingwu.yang@xxxxxxxxx>]

Since commit dc7b3eb900aa ("ipvs: Fix reuse connection if real server is
dead"), new connections to dead servers are redistributed immediately to
new servers.

Then commit d752c3645717 ("ipvs: allow rescheduling of new connections when
port reuse is detected") disable expire_nodest_conn if conn_reuse_mode is
0. And new connection may be distributed to a real server with weight 0.

Signed-off-by: yangxingwu <xingwu.yang@xxxxxxxxx>
---
 Documentation/networking/ipvs-sysctl.rst | 3 +--
 net/netfilter/ipvs/ip_vs_core.c          | 5 +++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/Documentation/networking/ipvs-sysctl.rst 
b/Documentation/networking/ipvs-sysctl.rst
index 2afccc63856e..1cfbf1add2fc 100644
--- a/Documentation/networking/ipvs-sysctl.rst
+++ b/Documentation/networking/ipvs-sysctl.rst
@@ -37,8 +37,7 @@ conn_reuse_mode - INTEGER
 
        0: disable any special handling on port reuse. The new
        connection will be delivered to the same real server that was
-       servicing the previous connection. This will effectively
-       disable expire_nodest_conn.
+       servicing the previous connection.
 
        bit 1: enable rescheduling of new connections when it is safe.
        That is, whenever expire_nodest_conn and for TCP sockets, when
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index 128690c512df..9279aed69e23 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -2042,14 +2042,15 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, 
struct sk_buff *skb, int
                             ipvs, af, skb, &iph);
 
        conn_reuse_mode = sysctl_conn_reuse_mode(ipvs);
-       if (conn_reuse_mode && !iph.fragoffs && is_new_conn(skb, &iph) && cp) {
+       if (!iph.fragoffs && is_new_conn(skb, &iph) && cp) {
                bool old_ct = false, resched = false;
 
                if (unlikely(sysctl_expire_nodest_conn(ipvs)) && cp->dest &&
                    unlikely(!atomic_read(&cp->dest->weight))) {
                        resched = true;
                        old_ct = ip_vs_conn_uses_old_conntrack(cp, skb);
-               } else if (is_new_conn_expected(cp, conn_reuse_mode)) {
+               } else if (conn_reuse_mode &&
+                          is_new_conn_expected(cp, conn_reuse_mode)) {
                        old_ct = ip_vs_conn_uses_old_conntrack(cp, skb);
                        if (!atomic_read(&cp->n_control)) {
                                resched = true;
-- 
2.30.2