svc: Move connection limit checking to its own function

Move the code that poaches connections when the connection limit is hit
to a subroutine to make the accept logic path easier to follow. Since this
is in the new connection path, it should not be a performance issue.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 29 insertions, 28 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 962dbf43a728..6e9dc8f96495 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -1105,17 +1105,30 @@ static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
 
         svc_sock_received(newsvsk);
 
-        /* make sure that we don't have too many active connections.
-         * If we have, something must be dropped.
-         *
-         * There's no point in trying to do random drop here for
-         * DoS prevention. The NFS clients does 1 reconnect in 15
-         * seconds. An attacker can easily beat that.
-         *
-         * The only somewhat efficient mechanism would be if drop
-         * old connections from the same IP first. But right now
-         * we don't even record the client IP in svc_sock.
-         */
+        if (serv->sv_stats)
+                serv->sv_stats->nettcpconn++;
+
+        return &newsvsk->sk_xprt;
+
+failed:
+        sock_release(newsock);
+        return NULL;
+}
+
+/*
+ * Make sure that we don't have too many active connections.  If we
+ * have, something must be dropped.
+ *
+ * There's no point in trying to do random drop here for DoS
+ * prevention. The NFS clients does 1 reconnect in 15 seconds. An
+ * attacker can easily beat that.
+ *
+ * The only somewhat efficient mechanism would be if drop old
+ * connections from the same IP first. But right now we don't even
+ * record the client IP in svc_sock.
+ */
+static void svc_check_conn_limits(struct svc_serv *serv)
+{
         if (serv->sv_tmpcnt > (serv->sv_nrthreads+3)*20) {
                 struct svc_sock *svsk = NULL;
                 spin_lock_bh(&serv->sv_lock);
@@ -1123,13 +1136,9 @@ static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
                         if (net_ratelimit()) {
                                 /* Try to help the admin */
                                 printk(KERN_NOTICE "%s: too many open TCP "
-                                        "sockets, consider increasing the "
-                                        "number of nfsd threads\n",
-                                                   serv->sv_name);
-                                printk(KERN_NOTICE
-                                       "%s: last TCP connect from %s\n",
-                                       serv->sv_name, __svc_print_addr(sin,
-                                                        buf, sizeof(buf)));
+                                       "sockets, consider increasing the "
+                                       "number of nfsd threads\n",
+                                       serv->sv_name);
                         }
                         /*
                          * Always select the oldest socket. It's not fair,
@@ -1147,17 +1156,7 @@ static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
                         svc_sock_enqueue(svsk);
                         svc_sock_put(svsk);
                 }
-
         }
-
-        if (serv->sv_stats)
-                serv->sv_stats->nettcpconn++;
-
-        return &newsvsk->sk_xprt;
-
-failed:
-        sock_release(newsock);
-        return NULL;
 }
 
 /*
@@ -1574,6 +1573,8 @@ svc_recv(struct svc_rqst *rqstp, long timeout)
         } else if (test_bit(SK_LISTENER, &svsk->sk_flags)) {
                 struct svc_xprt *newxpt;
                 newxpt = svsk->sk_xprt.xpt_ops->xpo_accept(&svsk->sk_xprt);
+                if (newxpt)
+                        svc_check_conn_limits(svsk->sk_server);
                 svc_sock_received(svsk);
         } else {
                 dprintk("svc: server %p, pool %u, socket %p, inuse=%d\n",