RDS: rds_send_xmit() locking/irq fixes

rds_message_put() cannot be called with irqs off, so move it after
irqs are re-enabled.

Spinlocks throughout the function do not to use _irqsave because
the lock of c_send_lock at top already disabled irqs.

Signed-off-by: Andy Grover <andy.grover@oracle.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/net/rds/send.c b/net/rds/send.c
index d4feec6ad09c..624a3dc7f060 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -168,7 +168,7 @@ int rds_send_xmit(struct rds_connection *conn)
                 if (!rm) {
                         unsigned int len;
 
-                        spin_lock_irqsave(&conn->c_lock, flags);
+                        spin_lock(&conn->c_lock);
 
                         if (!list_empty(&conn->c_send_queue)) {
                                 rm = list_entry(conn->c_send_queue.next,
@@ -183,7 +183,7 @@ int rds_send_xmit(struct rds_connection *conn)
                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
                         }
 
-                        spin_unlock_irqrestore(&conn->c_lock, flags);
+                        spin_unlock(&conn->c_lock);
 
                         if (!rm) {
                                 was_empty = 1;
@@ -199,11 +199,10 @@ int rds_send_xmit(struct rds_connection *conn)
                          */
                         if (rm->rdma.op_active &&
                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
-                                spin_lock_irqsave(&conn->c_lock, flags);
+                                spin_lock(&conn->c_lock);
                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
                                         list_move(&rm->m_conn_item, &to_be_dropped);
-                                spin_unlock_irqrestore(&conn->c_lock, flags);
-                                rds_message_put(rm);
+                                spin_unlock(&conn->c_lock);
                                 continue;
                         }
 
@@ -326,10 +325,6 @@ int rds_send_xmit(struct rds_connection *conn)
                 }
         }
 
-        /* Nuke any messages we decided not to retransmit. */
-        if (!list_empty(&to_be_dropped))
-                rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
-
         if (conn->c_trans->xmit_complete)
                 conn->c_trans->xmit_complete(conn);
 
@@ -347,6 +342,14 @@ int rds_send_xmit(struct rds_connection *conn)
          */
         spin_unlock_irqrestore(&conn->c_send_lock, flags);
 
+        /* Nuke any messages we decided not to retransmit. */
+        if (!list_empty(&to_be_dropped)) {
+                /* irqs on here, so we can put(), unlike above */
+                list_for_each_entry(rm, &to_be_dropped, m_conn_item)
+                        rds_message_put(rm);
+                rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
+        }
+
         if (send_quota == 0 && !was_empty) {
                 /* We exhausted the send quota, but there's work left to
                  * do. Return and (re-)schedule the send worker.