[patch] reducing arp locking

[Ingo Flaschberger]

Am 09.11.2012 15:03, schrieb Fabien Thomas:
> In in_arpinput only exclusive access to the entry is taken during the update no IF_AFDATA_LOCK that's why i was surprised.

what about this:
--
--- /usr/src/sys/netinet/if_ether.c_org 2012-11-09 16:15:43.000000000 +0000
+++ /usr/src/sys/netinet/if_ether.c     2012-11-09 16:16:37.000000000 +0000
@@ -685,7 +685,7 @@
         flags |= LLE_EXCLUSIVE;
         IF_AFDATA_LOCK(ifp);
         la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
-       IF_AFDATA_UNLOCK(ifp);
+
         if (la != NULL) {
                 /* the following is not an error when doing bridging */
                 if (!bridged && la->lle_tbl->llt_ifp != ifp && 
!carp_match) {
@@ -697,12 +697,14 @@
                                     ifp->if_addrlen, (u_char 
*)ar_sha(ah), ":",
                                     ifp->if_xname);
                         LLE_WUNLOCK(la);
+                       IF_AFDATA_UNLOCK(ifp);
                         goto reply;
                 }
                 if ((la->la_flags & LLE_VALID) &&
                     bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
                         if (la->la_flags & LLE_STATIC) {
                                 LLE_WUNLOCK(la);
+                               IF_AFDATA_UNLOCK(ifp);
                                 if (log_arp_permanent_modify)
                                         log(LOG_ERR,
                                             "arp: %*D attempts to modify "
@@ -725,6 +727,7 @@

                 if (ifp->if_addrlen != ah->ar_hln) {
                         LLE_WUNLOCK(la);
+                       IF_AFDATA_UNLOCK(ifp);
                         log(LOG_WARNING, "arp from %*D: addr len: new %d, "
                             "i/f %d (ignored)\n", ifp->if_addrlen,
                             (u_char *) ar_sha(ah), ":", ah->ar_hln,
@@ -763,14 +766,19 @@
                         la->la_numheld = 0;
                         memcpy(&sa, L3_ADDR(la), sizeof(sa));
                         LLE_WUNLOCK(la);
+                       IF_AFDATA_UNLOCK(ifp);
                         for (; m_hold != NULL; m_hold = m_hold_next) {
                                 m_hold_next = m_hold->m_nextpkt;
                                 m_hold->m_nextpkt = NULL;
                                 (*ifp->if_output)(ifp, m_hold, &sa, NULL);
                         }
-               } else
+               } else {
                         LLE_WUNLOCK(la);
-       }
+                       IF_AFDATA_UNLOCK(ifp);
+                }
+       } else {
+               IF_AFDATA_UNLOCK(ifp);
+        }
  reply:
         if (op != ARPOP_REQUEST)
                 goto drop;
--

Kind regards,
     Ingo Flaschberger