Convert ARP llinfo allocation to pool(9)

[Martin Pieuchot]

Some llinfo structures might be allocated in interrupt path when
ifa_rtrequest() is called, diff below convert such allocation to
pool(9), ok?

Index: netinet/if_ether.c
===================================================================
RCS file: /home/ncvs/src/sys/netinet/if_ether.c,v
retrieving revision 1.131
diff -u -p -r1.131 if_ether.c
--- netinet/if_ether.c  12 Jul 2014 18:44:23 -0000      1.131
+++ netinet/if_ether.c  11 Aug 2014 09:26:30 -0000
@@ -50,6 +50,8 @@
 #include <sys/timeout.h>
 #include <sys/kernel.h>
 #include <sys/syslog.h>
+#include <sys/queue.h>
+#include <sys/pool.h>
 
 #include <net/if.h>
 #include <net/if_dl.h>
@@ -87,6 +89,7 @@ struct llinfo_arp *arplookup(u_int32_t, 
 void in_arpinput(struct mbuf *);
 
 LIST_HEAD(, llinfo_arp) llinfo_arp;
+struct pool arp_pool;          /* pool for llinfo_arp structures */
 struct ifqueue arpintrq;
 int    arp_inuse, arp_allocated;
 int    arp_maxtries = 5;
@@ -147,6 +150,8 @@ arp_rtrequest(int req, struct rtentry *r
                static struct timeout arptimer_to;
 
                arpinit_done = 1;
+               pool_init(&arp_pool, sizeof(struct llinfo_arp), 0, 0, 0, "arp",
+                   NULL);
                IFQ_SET_MAXLEN(&arpintrq, 50);  /* XXX hate magic numbers */
                /*
                 * We generate expiration times from time.tv_sec
@@ -215,7 +220,7 @@ arp_rtrequest(int req, struct rtentry *r
                 * Case 2:  This route may come from cloning, or a manual route
                 * add with a LL address.
                 */
-               la = malloc(sizeof(*la), M_RTABLE, M_NOWAIT | M_ZERO);
+               la = pool_get(&arp_pool, PR_NOWAIT | PR_ZERO);
                rt->rt_llinfo = (caddr_t)la;
                if (la == NULL) {
                        log(LOG_DEBUG, "%s: malloc failed\n", __func__);
@@ -271,7 +276,7 @@ arp_rtrequest(int req, struct rtentry *r
                        la_hold_total--;
                        m_freem(m);
                }
-               free(la, M_RTABLE, 0);
+               pool_put(&arp_pool, la);
        }
 }