mld: add new workqueues for process mld events

When query/report packets are received, mld module processes them. But they are processed under BH context so it couldn't use sleepable functions. So, in order to switch context, the two workqueues are added which processes query and report event. In the struct inet6_dev, mc_{query | report}_queue are added so it is per-interface queue. And mc_{query | report}_work are workqueue structure. When the query or report event is received, skb is queued to proper queue and worker function is scheduled immediately. Workqueues and queues are protected by spinlock, which is mc_{query | report}_lock, and worker functions are protected by RTNL. Suggested-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>

Author: TaeheeYoo

include/net/if_inet6.h

@@ -125,7 +125,6 @@ struct ifmcaddr6 {
 unsigned intmca_flags;
 intmca_users;
 refcount_tmca_refcnt;
-spinlock_tmca_lock;
 unsigned longmca_cstamp;
 unsigned longmca_tstamp;
 struct rcu_headrcu;
@@ -183,6 +182,14 @@ struct inet6_dev {
 struct delayed_workmc_gq_work;/* general query work */
 struct delayed_workmc_ifc_work;/* interface change work */
 struct delayed_workmc_dad_work;/* dad complete mc work */
+struct delayed_workmc_query_work;/* mld query work */
+struct delayed_workmc_report_work;/* mld report work */
+
+struct sk_buff_headmc_query_queue;/* mld query queue */
+struct sk_buff_headmc_report_queue;/* mld report queue */
+
+spinlock_tmc_query_lock;/* mld query queue lock */
+spinlock_tmc_report_lock;/* mld query report lock */
 
 struct ifacaddr6*ac_list;
 rwlock_tlock;

include/net/mld.h

@@ -92,6 +92,9 @@ struct mld2_query {
 #define MLD_EXP_MIN_LIMIT32768UL
 #define MLDV1_MRD_MAX_COMPAT(MLD_EXP_MIN_LIMIT - 1)
 
+#define MLD_MAX_QUEUE8
+#define MLD_MAX_SKBS32
+
 static inline unsigned long mldv2_mrc(const struct mld2_query *mlh2)
 {
 /* RFC3810, 5.1.3. Maximum Response Code */

net/ipv6/icmp.c

@@ -944,11 +944,11 @@ static int icmpv6_rcv(struct sk_buff *skb)
 
 case ICMPV6_MGM_QUERY:
 igmp6_event_query(skb);
-break;
+return 0;
 
 case ICMPV6_MGM_REPORT:
 igmp6_event_report(skb);
-break;
+return 0;
 
 case ICMPV6_MGM_REDUCTION:
 case ICMPV6_NI_QUERY: