[PATCH net-next v3 01/11] net/rds: Don't sleep inside rds_ib_conn_path_shutdown

[Allison Henderson <achender@kernel.org>]

New rds rdma self tests exposed a hang when tearing down
the ib network configs.  This is caused by the shutdown worker
thread sleeping on the wait_event call, which blocks other work
items in the queue. Fix this by changing wait_event to
wait_event timeout, and looping until the wait check succeeds.

Signed-off-by: Allison Henderson <achender@kernel.org>
---
 net/rds/ib_cm.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index 0c64c504f79db..6b40345ba44d1 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -1038,6 +1038,19 @@ int rds_ib_conn_path_connect(struct rds_conn_path *cp)
 	return ret;
 }
 
+static unsigned long rds_ib_conn_path_shutdown_check_wait(struct rds_conn_path *cp)
+{
+	struct rds_connection *conn = cp->cp_conn;
+	struct rds_ib_connection *ic = conn->c_transport_data;
+
+	return (!ic->i_cm_id ||
+		(rds_ib_ring_empty(&ic->i_recv_ring) &&
+		 (atomic_read(&ic->i_signaled_sends) == 0) &&
+		 (atomic_read(&ic->i_fastreg_inuse_count)) == 0 &&
+		 (atomic_read(&ic->i_fastreg_wrs) == RDS_IB_DEFAULT_FR_WR))) ? 0
+		: msecs_to_jiffies(1000);
+}
+
 /*
  * This is so careful about only cleaning up resources that were built up
  * so that it can be called at any point during startup.  In fact it
@@ -1078,11 +1091,13 @@ void rds_ib_conn_path_shutdown(struct rds_conn_path *cp)
 		 * sends to complete we're ensured that there will be no
 		 * more tx processing.
 		 */
-		wait_event(rds_ib_ring_empty_wait,
-			   rds_ib_ring_empty(&ic->i_recv_ring) &&
-			   (atomic_read(&ic->i_signaled_sends) == 0) &&
-			   (atomic_read(&ic->i_fastreg_inuse_count) == 0) &&
-			   (atomic_read(&ic->i_fastreg_wrs) == RDS_IB_DEFAULT_FR_WR));
+		while (!wait_event_timeout(rds_ib_ring_empty_wait,
+					   rds_ib_conn_path_shutdown_check_wait(cp) == 0,
+					   msecs_to_jiffies(1000))) {
+			tasklet_schedule(&ic->i_send_tasklet);
+			tasklet_schedule(&ic->i_recv_tasklet);
+		}
+
 		tasklet_kill(&ic->i_send_tasklet);
 		tasklet_kill(&ic->i_recv_tasklet);
 
-- 
2.25.1