1 files changed, 22 insertions, 22 deletions

diff --git a/net/rds/connection.c b/net/rds/connection.c
index 87df15b9f8e4..180b83ab2607 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -62,6 +62,7 @@ static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
                 var |= RDS_INFO_CONNECTION_FLAG_##suffix;       \
 } while (0)
 
+/* rcu read lock must be held or the connection spinlock */
 static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
                                               __be32 laddr, __be32 faddr,
                                               struct rds_transport *trans)
@@ -69,7 +70,7 @@ static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
         struct rds_connection *conn, *ret = NULL;
         struct hlist_node *pos;
 
-        hlist_for_each_entry(conn, pos, head, c_hash_node) {
+        hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
                 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
                                 conn->c_trans == trans) {
                         ret = conn;
@@ -119,7 +120,8 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
         unsigned long flags;
         int ret;
 
-        spin_lock_irqsave(&rds_conn_lock, flags);
+
+        rcu_read_lock();
         conn = rds_conn_lookup(head, laddr, faddr, trans);
         if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
             !is_outgoing) {
@@ -130,7 +132,7 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
                 parent = conn;
                 conn = parent->c_passive;
         }
-        spin_unlock_irqrestore(&rds_conn_lock, flags);
+        rcu_read_unlock();
         if (conn)
                 goto out;
 
@@ -227,7 +229,7 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
                         kmem_cache_free(rds_conn_slab, conn);
                         conn = found;
                 } else {
-                        hlist_add_head(&conn->c_hash_node, head);
+                        hlist_add_head_rcu(&conn->c_hash_node, head);
                         rds_cong_add_conn(conn);
                         rds_conn_count++;
                 }
@@ -306,8 +308,13 @@ void rds_conn_shutdown(struct rds_connection *conn)
          * to the conn hash, so we never trigger a reconnect on this
          * conn - the reconnect is always triggered by the active peer. */
         cancel_delayed_work_sync(&conn->c_conn_w);
-        if (!hlist_unhashed(&conn->c_hash_node))
+        rcu_read_lock();
+        if (!hlist_unhashed(&conn->c_hash_node)) {
+                rcu_read_unlock();
                 rds_queue_reconnect(conn);
+        } else {
+                rcu_read_unlock();
+        }
 }
 
 /*
@@ -323,14 +330,12 @@ void rds_conn_destroy(struct rds_connection *conn)
 
         /* Ensure conn will not be scheduled for reconnect */
         spin_lock_irq(&rds_conn_lock);
-        hlist_del_init(&conn->c_hash_node);
+        hlist_del_init_rcu(&conn->c_hash_node);
         spin_unlock_irq(&rds_conn_lock);
 
-        /* wait for the rds thread to shut it down */
-        atomic_set(&conn->c_state, RDS_CONN_ERROR);
-        cancel_delayed_work(&conn->c_conn_w);
-        queue_work(rds_wq, &conn->c_down_w);
-        flush_workqueue(rds_wq);
+        synchronize_rcu();
+
+        rds_conn_shutdown(conn);
 
         /* tear down queued messages */
         list_for_each_entry_safe(rm, rtmp,
@@ -369,17 +374,16 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
         struct list_head *list;
         struct rds_connection *conn;
         struct rds_message *rm;
-        unsigned long flags;
         unsigned int total = 0;
         size_t i;
 
         len /= sizeof(struct rds_info_message);
 
-        spin_lock_irqsave(&rds_conn_lock, flags);
+        rcu_read_lock();
 
         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
              i++, head++) {
-                hlist_for_each_entry(conn, pos, head, c_hash_node) {
+                hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
                         if (want_send)
                                 list = &conn->c_send_queue;
                         else
@@ -399,8 +403,7 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
                         spin_unlock(&conn->c_lock);
                 }
         }
-
-        spin_unlock_irqrestore(&rds_conn_lock, flags);
+        rcu_read_unlock();
 
         lens->nr = total;
         lens->each = sizeof(struct rds_info_message);
@@ -430,19 +433,17 @@ void rds_for_each_conn_info(struct socket *sock, unsigned int len,
         uint64_t buffer[(item_len + 7) / 8];
         struct hlist_head *head;
         struct hlist_node *pos;
-        struct hlist_node *tmp;
         struct rds_connection *conn;
-        unsigned long flags;
         size_t i;
 
-        spin_lock_irqsave(&rds_conn_lock, flags);
+        rcu_read_lock();
 
         lens->nr = 0;
         lens->each = item_len;
 
         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
              i++, head++) {
-                hlist_for_each_entry_safe(conn, pos, tmp, head, c_hash_node) {
+                hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
 
                         /* XXX no c_lock usage.. */
                         if (!visitor(conn, buffer))
@@ -458,8 +459,7 @@ void rds_for_each_conn_info(struct socket *sock, unsigned int len,
                         lens->nr++;
                 }
         }
-
-        spin_unlock_irqrestore(&rds_conn_lock, flags);
+        rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);