From fffb9f1d9c5ec3ecdd516bcefb653099e05f6489 Mon Sep 17 00:00:00 2001
From: "Bjoern A. Zeeb" <bz@FreeBSD.org>
Date: Tue, 9 Feb 2010 21:31:53 +0000
Subject: [PATCH] Properly free resources when destroying the TCP hostcache
 while tearing down a network stack (in the VIMAGE jail+vnet case).

For that break out the logic from tcp_hc_purge() into an internal
function we can call from both, the sysctl handler and the
tcp_hc_destroy().

Sponsored by:	ISPsystem
Reviewed by:	silby, lstewart
MFC After:	8 days
---
 sys/netinet/tcp_hostcache.c | 44 +++++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/sys/netinet/tcp_hostcache.c b/sys/netinet/tcp_hostcache.c
index acbc860a26ed..a0c4012f21f0 100644
--- a/sys/netinet/tcp_hostcache.c
+++ b/sys/netinet/tcp_hostcache.c
@@ -115,6 +115,7 @@ static VNET_DEFINE(struct callout, tcp_hc_callout);
 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
+static void tcp_hc_purge_internal(int);
 static void tcp_hc_purge(void *);
 
 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0,
@@ -235,10 +236,19 @@ tcp_hc_init(void)
 void
 tcp_hc_destroy(void)
 {
-
-	/* XXX TODO walk the hashtable and free all entries  */
+	int i;
 
 	callout_drain(&V_tcp_hc_callout);
+
+	/* Purge all hc entries. */
+	tcp_hc_purge_internal(1);
+
+	/* Free the uma zone and the allocated hash table. */
+	uma_zdestroy(V_tcp_hostcache.zone);
+
+	for (i = 0; i < V_tcp_hostcache.hashsize; i++)
+		mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
+	free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
 }
 #endif
 
@@ -633,22 +643,14 @@ sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
 }
 
 /*
- * Expire and purge (old|all) entries in the tcp_hostcache.  Runs
- * periodically from the callout.
+ * Caller has to make sure the curvnet is set properly.
  */
 static void
-tcp_hc_purge(void *arg)
+tcp_hc_purge_internal(int all)
 {
-	CURVNET_SET((struct vnet *) arg);
 	struct hc_metrics *hc_entry, *hc_next;
-	int all = 0;
 	int i;
 
-	if (V_tcp_hostcache.purgeall) {
-		all = 1;
-		V_tcp_hostcache.purgeall = 0;
-	}
-
 	for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
 		THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 		TAILQ_FOREACH_SAFE(hc_entry,
@@ -664,6 +666,24 @@ tcp_hc_purge(void *arg)
 		}
 		THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
 	}
+}
+
+/*
+ * Expire and purge (old|all) entries in the tcp_hostcache.  Runs
+ * periodically from the callout.
+ */
+static void
+tcp_hc_purge(void *arg)
+{
+	CURVNET_SET((struct vnet *) arg);
+	int all = 0;
+
+	if (V_tcp_hostcache.purgeall) {
+		all = 1;
+		V_tcp_hostcache.purgeall = 0;
+	}
+
+	tcp_hc_purge_internal(all);
 
 	callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
 	    tcp_hc_purge, arg);