ipvs: convert sh scheduler to rcu

Use the 3 new methods to reassign dests.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

diff --git a/net/netfilter/ipvs/ip_vs_sh.c b/net/netfilter/ipvs/ip_vs_sh.c
index e331269..55e76d8 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_sh.c
+++ b/net/netfilter/ipvs/ip_vs_sh.c
@@ -53,7 +53,7 @@
  *      IPVS SH bucket
  */
 struct ip_vs_sh_bucket {
-       struct ip_vs_dest       *dest;          /* real server (cache) */
+       struct ip_vs_dest __rcu *dest;  /* real server (cache) */
 };
 
 /*
@@ -66,6 +66,10 @@ struct ip_vs_sh_bucket {
 #define IP_VS_SH_TAB_SIZE               (1 << IP_VS_SH_TAB_BITS)
 #define IP_VS_SH_TAB_MASK               (IP_VS_SH_TAB_SIZE - 1)
 
+struct ip_vs_sh_state {
+       struct ip_vs_sh_bucket          buckets[IP_VS_SH_TAB_SIZE];
+       struct rcu_head                 rcu_head;
+};
 
 /*
  *     Returns hash value for IPVS SH entry
@@ -87,10 +91,9 @@ static inline unsigned int ip_vs_sh_hashkey(int af, const union nf_inet_addr *ad
  *      Get ip_vs_dest associated with supplied parameters.
  */
 static inline struct ip_vs_dest *
-ip_vs_sh_get(int af, struct ip_vs_sh_bucket *tbl,
-            const union nf_inet_addr *addr)
+ip_vs_sh_get(int af, struct ip_vs_sh_state *s, const union nf_inet_addr *addr)
 {
-       return (tbl[ip_vs_sh_hashkey(af, addr)]).dest;
+       return rcu_dereference(s->buckets[ip_vs_sh_hashkey(af, addr)].dest);
 }
 
 
@@ -98,27 +101,32 @@ ip_vs_sh_get(int af, struct ip_vs_sh_bucket *tbl,
  *      Assign all the hash buckets of the specified table with the service.
  */
 static int
-ip_vs_sh_assign(struct ip_vs_sh_bucket *tbl, struct ip_vs_service *svc)
+ip_vs_sh_reassign(struct ip_vs_sh_state *s, struct ip_vs_service *svc)
 {
        int i;
        struct ip_vs_sh_bucket *b;
        struct list_head *p;
        struct ip_vs_dest *dest;
        int d_count;
+       bool empty;
 
-       b = tbl;
+       b = &s->buckets[0];
        p = &svc->destinations;
+       empty = list_empty(p);
        d_count = 0;
        for (i=0; i<IP_VS_SH_TAB_SIZE; i++) {
-               if (list_empty(p)) {
-                       b->dest = NULL;
-               } else {
+               dest = rcu_dereference_protected(b->dest, 1);
+               if (dest)
+                       ip_vs_dest_put(dest);
+               if (empty)
+                       RCU_INIT_POINTER(b->dest, NULL);
+               else {
                        if (p == &svc->destinations)
                                p = p->next;
 
                        dest = list_entry(p, struct ip_vs_dest, n_list);
-                       atomic_inc(&dest->refcnt);
-                       b->dest = dest;
+                       ip_vs_dest_hold(dest);
+                       RCU_INIT_POINTER(b->dest, dest);
 
                        IP_VS_DBG_BUF(6, "assigned i: %d dest: %s weight: %d\n",
                                      i, IP_VS_DBG_ADDR(svc->af, &dest->addr),
@@ -140,16 +148,18 @@ ip_vs_sh_assign(struct ip_vs_sh_bucket *tbl, struct ip_vs_service *svc)
 /*
  *      Flush all the hash buckets of the specified table.
  */
-static void ip_vs_sh_flush(struct ip_vs_sh_bucket *tbl)
+static void ip_vs_sh_flush(struct ip_vs_sh_state *s)
 {
        int i;
        struct ip_vs_sh_bucket *b;
+       struct ip_vs_dest *dest;
 
-       b = tbl;
+       b = &s->buckets[0];
        for (i=0; i<IP_VS_SH_TAB_SIZE; i++) {
-               if (b->dest) {
-                       atomic_dec(&b->dest->refcnt);
-                       b->dest = NULL;
+               dest = rcu_dereference_protected(b->dest, 1);
+               if (dest) {
+                       ip_vs_dest_put(dest);
+                       RCU_INIT_POINTER(b->dest, NULL);
                }
                b++;
        }
@@ -158,21 +168,20 @@ static void ip_vs_sh_flush(struct ip_vs_sh_bucket *tbl)
 
 static int ip_vs_sh_init_svc(struct ip_vs_service *svc)
 {
-       struct ip_vs_sh_bucket *tbl;
+       struct ip_vs_sh_state *s;
 
        /* allocate the SH table for this service */
-       tbl = kmalloc(sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE,
-                     GFP_KERNEL);
-       if (tbl == NULL)
+       s = kzalloc(sizeof(struct ip_vs_sh_state), GFP_KERNEL);
+       if (s == NULL)
                return -ENOMEM;
 
-       svc->sched_data = tbl;
+       svc->sched_data = s;
        IP_VS_DBG(6, "SH hash table (memory=%Zdbytes) allocated for "
                  "current service\n",
                  sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE);
 
-       /* assign the hash buckets with the updated service */
-       ip_vs_sh_assign(tbl, svc);
+       /* assign the hash buckets with current dests */
+       ip_vs_sh_reassign(s, svc);
 
        return 0;
 }
@@ -180,13 +189,13 @@ static int ip_vs_sh_init_svc(struct ip_vs_service *svc)
 
 static int ip_vs_sh_done_svc(struct ip_vs_service *svc)
 {
-       struct ip_vs_sh_bucket *tbl = svc->sched_data;
+       struct ip_vs_sh_state *s = svc->sched_data;
 
        /* got to clean up hash buckets here */
-       ip_vs_sh_flush(tbl);
+       ip_vs_sh_flush(s);
 
        /* release the table itself */
-       kfree(svc->sched_data);
+       kfree_rcu(s, rcu_head);
        IP_VS_DBG(6, "SH hash table (memory=%Zdbytes) released\n",
                  sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE);
 
@@ -194,15 +203,13 @@ static int ip_vs_sh_done_svc(struct ip_vs_service *svc)
 }
 
 
-static int ip_vs_sh_update_svc(struct ip_vs_service *svc)
+static int ip_vs_sh_dest_changed(struct ip_vs_service *svc,
+                                struct ip_vs_dest *dest)
 {
-       struct ip_vs_sh_bucket *tbl = svc->sched_data;
-
-       /* got to clean up hash buckets here */
-       ip_vs_sh_flush(tbl);
+       struct ip_vs_sh_state *s = svc->sched_data;
 
        /* assign the hash buckets with the updated service */
-       ip_vs_sh_assign(tbl, svc);
+       ip_vs_sh_reassign(s, svc);
 
        return 0;
 }
@@ -225,15 +232,15 @@ static struct ip_vs_dest *
 ip_vs_sh_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
 {
        struct ip_vs_dest *dest;
-       struct ip_vs_sh_bucket *tbl;
+       struct ip_vs_sh_state *s;
        struct ip_vs_iphdr iph;
 
        ip_vs_fill_iph_addr_only(svc->af, skb, &iph);
 
        IP_VS_DBG(6, "ip_vs_sh_schedule(): Scheduling...\n");
 
-       tbl = (struct ip_vs_sh_bucket *)svc->sched_data;
-       dest = ip_vs_sh_get(svc->af, tbl, &iph.saddr);
+       s = (struct ip_vs_sh_state *) svc->sched_data;
+       dest = ip_vs_sh_get(svc->af, s, &iph.saddr);
        if (!dest
            || !(dest->flags & IP_VS_DEST_F_AVAILABLE)
            || atomic_read(&dest->weight) <= 0
@@ -262,7 +269,9 @@ static struct ip_vs_scheduler ip_vs_sh_scheduler =
        .n_list  =              LIST_HEAD_INIT(ip_vs_sh_scheduler.n_list),
        .init_service =         ip_vs_sh_init_svc,
        .done_service =         ip_vs_sh_done_svc,
-       .update_service =       ip_vs_sh_update_svc,
+       .add_dest =             ip_vs_sh_dest_changed,
+       .del_dest =             ip_vs_sh_dest_changed,
+       .upd_dest =             ip_vs_sh_dest_changed,
        .schedule =             ip_vs_sh_schedule,
 };