rds: block ints when acquiring c_lock in rds_conn_message_info()

conn->c_lock is acquired in interrupt context.  rds_conn_message_info() is
called from user context and was acquiring c_lock without blocking interrupts,
leading to possible deadlocks.

Signed-off-by: Zach Brown <zach.brown@oracle.com>

diff --git a/net/rds/connection.c b/net/rds/connection.c
index 5bd96d5..5bb0eec 100644 (file)
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -375,6 +375,7 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
        struct rds_connection *conn;
        struct rds_message *rm;
        unsigned int total = 0;
+       unsigned long flags;
        size_t i;
 
        len /= sizeof(struct rds_info_message);
@@ -389,7 +390,7 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
                        else
                                list = &conn->c_retrans;
 
-                       spin_lock(&conn->c_lock);
+                       spin_lock_irqsave(&conn->c_lock, flags);
 
                        /* XXX too lazy to maintain counts.. */
                        list_for_each_entry(rm, list, m_conn_item) {
@@ -400,7 +401,7 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
                                                          conn->c_faddr, 0);
                        }
 
-                       spin_unlock(&conn->c_lock);
+                       spin_unlock_irqrestore(&conn->c_lock, flags);
                }
        }
        rcu_read_unlock();