Use mq_delist() to fetch the ARP mbuf hold queue once and feed the

mbuf list to if_output().
OK sashan@ mvs@

diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c
index 0945cd3..e6615ca 100644 (file)
--- a/sys/netinet/if_ether.c
+++ b/sys/netinet/if_ether.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_ether.c,v 1.247 2021/04/28 10:33:34 bluhm Exp $    */
+/*     $OpenBSD: if_ether.c,v 1.248 2021/04/28 21:21:44 bluhm Exp $    */
 /*     $NetBSD: if_ether.c,v 1.31 1996/05/11 12:59:58 mycroft Exp $    */
 
 /*
@@ -611,7 +611,9 @@ arpcache(struct ifnet *ifp, struct ether_arp *ea, struct rtentry *rt)
        struct in_addr *spa = (struct in_addr *)ea->arp_spa;
        char addr[INET_ADDRSTRLEN];
        struct ifnet *rifp;
+       struct mbuf_list ml;
        struct mbuf *m;
+       unsigned int len;
        int changed = 0;
 
        KERNEL_ASSERT_LOCKED();
@@ -683,21 +685,16 @@ arpcache(struct ifnet *ifp, struct ether_arp *ea, struct rtentry *rt)
 
        la->la_asked = 0;
        la->la_refreshed = 0;
-       while ((m = mq_dequeue(&la->la_mq)) != NULL) {
-               unsigned int len;
-
-               atomic_dec_int(&la_hold_total);
-               len = mq_len(&la->la_mq);
-
+       mq_delist(&la->la_mq, &ml);
+       len = ml_len(&ml);
+       while ((m = ml_dequeue(&ml)) != NULL)
                ifp->if_output(ifp, m, rt_key(rt), rt);
-
-               /* XXXSMP we discard if other CPU enqueues */
-               if (mq_len(&la->la_mq) > len) {
-                       /* mbuf is back in queue. Discard. */
-                       atomic_sub_int(&la_hold_total, mq_purge(&la->la_mq));
-                       break;
-               }
-       }
+       /* XXXSMP we discard if other CPU enqueues */
+       if (mq_len(&la->la_mq) > 0) {
+               /* mbuf is back in queue. Discard. */
+               atomic_sub_int(&la_hold_total, len + mq_purge(&la->la_mq));
+       } else
+               atomic_sub_int(&la_hold_total, len);
 
        return (0);
 }