From 8e054749e4505c83733044620fcba6ebec0da588 Mon Sep 17 00:00:00 2001
From: dyoung <dyoung@NetBSD.org>
Date: Tue, 3 May 2011 16:00:29 +0000
Subject: [PATCH] arp_drain() may be called with locks held, so instead of
 doing any work in arp_drain(), set a drain-needed flag.  Do the work in the
 fasttimo handler.

Contributed by Coyote Point Systems, Inc.
---
 sys/netinet/if_arp.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/sys/netinet/if_arp.c b/sys/netinet/if_arp.c
index 8d623a9a7c5b..f1863a6201c6 100644
--- a/sys/netinet/if_arp.c
+++ b/sys/netinet/if_arp.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: if_arp.c,v 1.150 2011/02/01 01:39:21 matt Exp $	*/
+/*	$NetBSD: if_arp.c,v 1.151 2011/05/03 16:00:29 dyoung Exp $	*/
 
 /*-
  * Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc.
@@ -68,7 +68,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.150 2011/02/01 01:39:21 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.151 2011/05/03 16:00:29 dyoung Exp $");
 
 #include "opt_ddb.h"
 #include "opt_inet.h"
@@ -151,6 +151,7 @@ static	struct llinfo_arp *arplookup1(struct mbuf *, const struct in_addr *,
 static	struct llinfo_arp *arplookup(struct mbuf *, const struct in_addr *,
 					  int, int);
 static	void in_arpinput(struct mbuf *);
+static	void arp_drainstub(void);
 
 LIST_HEAD(, llinfo_arp) llinfo_arp;
 struct	ifqueue arpintrq = {
@@ -188,6 +189,8 @@ static void db_print_llinfo(void *);
 static int db_show_rtentry(struct rtentry *, void *);
 #endif
 
+static int arp_drainwanted;
+
 /*
  * this should be elsewhere.
  */
@@ -224,6 +227,15 @@ lla_snprintf(u_int8_t *adrp, int len)
 
 DOMAIN_DEFINE(arpdomain);	/* forward declare and add to link set */
 
+static void
+arp_fasttimo(void)
+{
+	if (arp_drainwanted) {
+		arp_drain();
+		arp_drainwanted = 0;
+	}
+}
+
 const struct protosw arpsw[] = {
 	{ .pr_type = 0,
 	  .pr_domain = &arpdomain,
@@ -235,9 +247,9 @@ const struct protosw arpsw[] = {
 	  .pr_ctloutput = 0,
 	  .pr_usrreq =  0,
 	  .pr_init = arp_init,
-	  .pr_fasttimo = 0,
+	  .pr_fasttimo = arp_fasttimo,
 	  .pr_slowtimo = 0,
-	  .pr_drain = arp_drain,
+	  .pr_drain = arp_drainstub,
 	}
 };
 
@@ -328,6 +340,12 @@ arp_init(void)
 	arpstat_percpu = percpu_alloc(sizeof(uint64_t) * ARP_NSTATS);
 }
 
+static void
+arp_drainstub(void)
+{
+	arp_drainwanted = 1;
+}
+
 /*
  * ARP protocol drain routine.  Called when memory is in short supply.
  * Called at splvm();  don't acquire softnet_lock as can be called from