1 files changed, 36 insertions, 18 deletions

diff --git a/net/rds/connection.c b/net/rds/connection.c
index d14445c48304..cc8b568c0c84 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -126,7 +126,7 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
                                        struct rds_transport *trans, gfp_t gfp,
                                        int is_outgoing)
 {
-        struct rds_connection *conn, *tmp, *parent = NULL;
+        struct rds_connection *conn, *parent = NULL;
         struct hlist_head *head = rds_conn_bucket(laddr, faddr);
         unsigned long flags;
         int ret;
@@ -155,7 +155,6 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
         }
 
         INIT_HLIST_NODE(&conn->c_hash_node);
-        conn->c_version = RDS_PROTOCOL_3_0;
         conn->c_laddr = laddr;
         conn->c_faddr = faddr;
         spin_lock_init(&conn->c_lock);
@@ -211,26 +210,40 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
           trans->t_name ? trans->t_name : "[unknown]",
           is_outgoing ? "(outgoing)" : "");
 
+        /*
+         * Since we ran without holding the conn lock, someone could
+         * have created the same conn (either normal or passive) in the
+         * interim. We check while holding the lock. If we won, we complete
+         * init and return our conn. If we lost, we rollback and return the
+         * other one.
+         */
         spin_lock_irqsave(&rds_conn_lock, flags);
-        if (parent == NULL) {
-                tmp = rds_conn_lookup(head, laddr, faddr, trans);
-                if (tmp == NULL)
-                        hlist_add_head(&conn->c_hash_node, head);
-        } else {
-                tmp = parent->c_passive;
-                if (!tmp)
+        if (parent) {
+                /* Creating passive conn */
+                if (parent->c_passive) {
+                        trans->conn_free(conn->c_transport_data);
+                        kmem_cache_free(rds_conn_slab, conn);
+                        conn = parent->c_passive;
+                } else {
                         parent->c_passive = conn;
-        }
-
-        if (tmp) {
-                trans->conn_free(conn->c_transport_data);
-                kmem_cache_free(rds_conn_slab, conn);
-                conn = tmp;
+                        rds_cong_add_conn(conn);
+                        rds_conn_count++;
+                }
         } else {
-                rds_cong_add_conn(conn);
-                rds_conn_count++;
+                /* Creating normal conn */
+                struct rds_connection *found;
+
+                found = rds_conn_lookup(head, laddr, faddr, trans);
+                if (found) {
+                        trans->conn_free(conn->c_transport_data);
+                        kmem_cache_free(rds_conn_slab, conn);
+                        conn = found;
+                } else {
+                        hlist_add_head(&conn->c_hash_node, head);
+                        rds_cong_add_conn(conn);
+                        rds_conn_count++;
+                }
         }
-
         spin_unlock_irqrestore(&rds_conn_lock, flags);
 
 out:
@@ -242,12 +255,14 @@ struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
 {
         return __rds_conn_create(laddr, faddr, trans, gfp, 0);
 }
+EXPORT_SYMBOL_GPL(rds_conn_create);
 
 struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
                                        struct rds_transport *trans, gfp_t gfp)
 {
         return __rds_conn_create(laddr, faddr, trans, gfp, 1);
 }
+EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
 
 void rds_conn_destroy(struct rds_connection *conn)
 {
@@ -290,6 +305,7 @@ void rds_conn_destroy(struct rds_connection *conn)
 
         rds_conn_count--;
 }
+EXPORT_SYMBOL_GPL(rds_conn_destroy);
 
 static void rds_conn_message_info(struct socket *sock, unsigned int len,
                                   struct rds_info_iterator *iter,
@@ -393,6 +409,7 @@ void rds_for_each_conn_info(struct socket *sock, unsigned int len,
 
         spin_unlock_irqrestore(&rds_conn_lock, flags);
 }
+EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
 
 static int rds_conn_info_visitor(struct rds_connection *conn,
                                   void *buffer)
@@ -468,6 +485,7 @@ void rds_conn_drop(struct rds_connection *conn)
         atomic_set(&conn->c_state, RDS_CONN_ERROR);
         queue_work(rds_wq, &conn->c_down_w);
 }
+EXPORT_SYMBOL_GPL(rds_conn_drop);
 
 /*
  * An error occurred on the connection