[src/trunk]: src/sys/netinet arp_drain() may be called with locks held, so in...

[dyoung <dyoung%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/09ad232157b1
branches:  trunk
changeset: 764772:09ad232157b1
user:      dyoung <dyoung%NetBSD.org@localhost>
date:      Tue May 03 16:00:29 2011 +0000

description:
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.

diffstat:

 sys/netinet/if_arp.c |  26 ++++++++++++++++++++++----
 1 files changed, 22 insertions(+), 4 deletions(-)

diffs (76 lines):

diff -r d162632d83fc -r 09ad232157b1 sys/netinet/if_arp.c
--- a/sys/netinet/if_arp.c      Tue May 03 15:13:50 2011 +0000
+++ b/sys/netinet/if_arp.c      Tue May 03 16:00:29 2011 +0000
@@ -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 *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 int db_show_rtentry(struct rtentry *, void *);
 #endif
 
+static int arp_drainwanted;
+
 /*
  * this should be elsewhere.
  */
@@ -224,6 +227,15 @@
 
 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 @@
          .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 @@
        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