Document that igmp_timers_are_running and mld6_timers_are_running

are protected by netlock.  They are only used as shortcut in fast
timer.
Common prefix in mld6.c is mld6.
OK mvs@

diff --git a/sys/netinet/igmp.c b/sys/netinet/igmp.c
index 251ad71..9e01ea8 100644 (file)
--- a/sys/netinet/igmp.c
+++ b/sys/netinet/igmp.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: igmp.c,v 1.79 2022/08/21 23:04:45 bluhm Exp $ */
+/*     $OpenBSD: igmp.c,v 1.80 2022/08/22 21:02:44 bluhm Exp $ */
 /*     $NetBSD: igmp.c,v 1.15 1996/02/13 23:41:25 christos Exp $       */
 
 /*
@@ -96,7 +96,7 @@
 
 #define IP_MULTICASTOPTS       0
 
-int            igmp_timers_are_running;
+int    igmp_timers_are_running;        /* [N] shortcut for fast timer */
 static LIST_HEAD(, router_info) rti_head;
 static struct mbuf *router_alert;
 struct cpumem *igmpcounters;
@@ -529,8 +529,9 @@ igmp_fasttimo(void)
        /*
         * Quick check to see if any work needs to be done, in order
         * to minimize the overhead of fasttimo processing.
-        * Variable igmp_timers_are_running is read atomically.  In case we
-        * miss a fast timer due to MP races, just run it next time.
+        * Variable igmp_timers_are_running is read atomically, but without
+        * lock intensionally.  In case it is not set due to MP races, we may
+        * miss to check the timers.  Then run the loop at next fast timeout.
         */
        if (!igmp_timers_are_running)
                return;

diff --git a/sys/netinet6/mld6.c b/sys/netinet6/mld6.c
index 31c0256..a580096 100644 (file)
--- a/sys/netinet6/mld6.c
+++ b/sys/netinet6/mld6.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: mld6.c,v 1.57 2022/08/21 23:04:45 bluhm Exp $ */
+/*     $OpenBSD: mld6.c,v 1.58 2022/08/22 21:02:44 bluhm Exp $ */
 /*     $KAME: mld6.c,v 1.26 2001/02/16 14:50:35 itojun Exp $   */
 
 /*
@@ -84,7 +84,7 @@
 #include <netinet6/mld6_var.h>
 
 static struct ip6_pktopts ip6_opts;
-static int mld_timers_are_running;
+int    mld6_timers_are_running;        /* [N] shortcut for fast timer */
 /* XXX: These are necessary for KAME's link-local hack */
 static struct in6_addr mld_all_nodes_linklocal = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
 static struct in6_addr mld_all_routers_linklocal = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
@@ -99,7 +99,7 @@ mld6_init(void)
        struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
        u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
 
-       mld_timers_are_running = 0;
+       mld6_timers_are_running = 0;
 
        /* ip6h_nxt will be fill in later */
        hbh->ip6h_len = 0;      /* (8 >> 3) - 1 */
@@ -136,7 +136,7 @@ mld6_start_listening(struct in6_multi *in6m)
                    MLD_RANDOM_DELAY(MLD_V1_MAX_RI *
                    PR_FASTHZ);
                in6m->in6m_state = MLD_IREPORTEDLAST;
-               mld_timers_are_running = 1;
+               mld6_timers_are_running = 1;
        }
 }
 
@@ -266,7 +266,7 @@ mld6_input(struct mbuf *m, int off)
                                        in6m->in6m_timer > timer) {
                                        in6m->in6m_timer =
                                            MLD_RANDOM_DELAY(timer);
-                                       mld_timers_are_running = 1;
+                                       mld6_timers_are_running = 1;
                                }
                        }
                }
@@ -330,15 +330,16 @@ mld6_fasttimeo(void)
        /*
         * Quick check to see if any work needs to be done, in order
         * to minimize the overhead of fasttimo processing.
-        * Variable mld_timers_are_running is read atomically.  In case we
-        * miss a fast timer due to MP races, just run it next time.
+        * Variable mld6_timers_are_running is read atomically, but without
+        * lock intensionally.  In case it is not set due to MP races, we may
+        * miss to check the timers.  Then run the loop at next fast timeout.
         */
-       if (!mld_timers_are_running)
+       if (!mld6_timers_are_running)
                return;
 
        NET_LOCK();
 
-       mld_timers_are_running = 0;
+       mld6_timers_are_running = 0;
        TAILQ_FOREACH(ifp, &ifnet, if_list)
                mld6_checktimer(ifp);
 
@@ -363,7 +364,7 @@ mld6_checktimer(struct ifnet *ifp)
                        mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
                        in6m->in6m_state = MLD_IREPORTEDLAST;
                } else {
-                       mld_timers_are_running = 1;
+                       mld6_timers_are_running = 1;
                }
        }
 }