1 files changed, 47 insertions, 23 deletions

diff --git a/net/sctp/bind_addr.c b/net/sctp/bind_addr.c
index fdb287a9e2e2..d35cbf5aae33 100644
--- a/net/sctp/bind_addr.c
+++ b/net/sctp/bind_addr.c
@@ -163,9 +163,15 @@ int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
                 addr->a.v4.sin_port = htons(bp->port);
 
         addr->use_as_src = use_as_src;
+        addr->valid = 1;
 
         INIT_LIST_HEAD(&addr->list);
-        list_add_tail(&addr->list, &bp->address_list);
+        INIT_RCU_HEAD(&addr->rcu);
+
+        /* We always hold a socket lock when calling this function,
+         * and that acts as a writer synchronizing lock.
+         */
+        list_add_tail_rcu(&addr->list, &bp->address_list);
         SCTP_DBG_OBJCNT_INC(addr);
 
         return 0;
@@ -174,23 +180,35 @@ int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
 /* Delete an address from the bind address list in the SCTP_bind_addr
  * structure.
  */
-int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)
+int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr,
+                        void (*rcu_call)(struct rcu_head *head,
+                                         void (*func)(struct rcu_head *head)))
 {
-        struct list_head *pos, *temp;
-        struct sctp_sockaddr_entry *addr;
+        struct sctp_sockaddr_entry *addr, *temp;
 
-        list_for_each_safe(pos, temp, &bp->address_list) {
-                addr = list_entry(pos, struct sctp_sockaddr_entry, list);
+        /* We hold the socket lock when calling this function,
+         * and that acts as a writer synchronizing lock.
+         */
+        list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
                 if (sctp_cmp_addr_exact(&addr->a, del_addr)) {
                         /* Found the exact match. */
-                        list_del(pos);
-                        kfree(addr);
-                        SCTP_DBG_OBJCNT_DEC(addr);
-
-                        return 0;
+                        addr->valid = 0;
+                        list_del_rcu(&addr->list);
+                        break;
                 }
         }
 
+        /* Call the rcu callback provided in the args.  This function is
+         * called by both BH packet processing and user side socket option
+         * processing, but it works on different lists in those 2 contexts.
+         * Each context provides it's own callback, whether call_rcu_bh()
+         * or call_rcu(), to make sure that we wait for an appropriate time.
+         */
+        if (addr && !addr->valid) {
+                rcu_call(&addr->rcu, sctp_local_addr_free);
+                SCTP_DBG_OBJCNT_DEC(addr);
+        }
+
         return -EINVAL;
 }
 
@@ -300,15 +318,20 @@ int sctp_bind_addr_match(struct sctp_bind_addr *bp,
                          struct sctp_sock *opt)
 {
         struct sctp_sockaddr_entry *laddr;
-        struct list_head *pos;
-
-        list_for_each(pos, &bp->address_list) {
-                laddr = list_entry(pos, struct sctp_sockaddr_entry, list);
-                if (opt->pf->cmp_addr(&laddr->a, addr, opt))
-                        return 1;
+        int match = 0;
+
+        rcu_read_lock();
+        list_for_each_entry_rcu(laddr, &bp->address_list, list) {
+                if (!laddr->valid)
+                        continue;
+                if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
+                        match = 1;
+                        break;
+                }
         }
+        rcu_read_unlock();
 
-        return 0;
+        return match;
 }
 
 /* Find the first address in the bind address list that is not present in
@@ -323,18 +346,19 @@ union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
         union sctp_addr                 *addr;
         void                            *addr_buf;
         struct sctp_af                  *af;
-        struct list_head                *pos;
         int                             i;
 
-        list_for_each(pos, &bp->address_list) {
-                laddr = list_entry(pos, struct sctp_sockaddr_entry, list);
-
+        /* This is only called sctp_send_asconf_del_ip() and we hold
+         * the socket lock in that code patch, so that address list
+         * can't change.
+         */
+        list_for_each_entry(laddr, &bp->address_list, list) {
                 addr_buf = (union sctp_addr *)addrs;
                 for (i = 0; i < addrcnt; i++) {
                         addr = (union sctp_addr *)addr_buf;
                         af = sctp_get_af_specific(addr->v4.sin_family);
                         if (!af)
-                                return NULL;
+                                break;
 
                         if (opt->pf->cmp_addr(&laddr->a, addr, opt))
                                 break;