diff options
| -rw-r--r-- | net/rds/connection.c | 48 |
1 files changed, 31 insertions, 17 deletions
diff --git a/net/rds/connection.c b/net/rds/connection.c index 605fe3f60de..b420a20d84f 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; @@ -210,26 +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: |