[openib-general] [PATCH] 2.6.20 ib_cm: limit cm message timeouts

[Sean Hefty]

Limit the timeout that the ib_cm will wait to receive a response to
a message, to avoid excessively large (on the order of hours) timeout
values.  This prevents consuming resources tracking requests for
extended periods of time.

This helps correct for a bug in the SRP Engenio target sending a large
value (> 1 hour) as a service timeout.

Signed-off-by: Sean Hefty <sean.hefty at intel.com>
---
 drivers/infiniband/core/cm.c |   30 +++++++++++++++++++-----------
 1 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index d446998..147b41e 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -54,6 +54,12 @@ MODULE_AUTHOR("Sean Hefty");
 MODULE_DESCRIPTION("InfiniBand CM");
 MODULE_LICENSE("Dual BSD/GPL");
 
+/*
+ * Limit CM msg timeouts to something reasonable.
+ * 8 seconds, with up to 15 retries, gives per msg timeout of 2 min.
+ */
+#define IB_CM_MAX_TIMEOUT 21
+
 static void cm_add_one(struct ib_device *device);
 static void cm_remove_one(struct ib_device *device);
 
@@ -888,12 +894,12 @@ static void cm_format_req(struct cm_req_msg *req_msg,
 	cm_req_set_resp_res(req_msg, param->responder_resources);
 	cm_req_set_init_depth(req_msg, param->initiator_depth);
 	cm_req_set_remote_resp_timeout(req_msg,
-				       param->remote_cm_response_timeout);
+		min((u8) IB_CM_MAX_TIMEOUT, param->remote_cm_response_timeout));
 	cm_req_set_qp_type(req_msg, param->qp_type);
 	cm_req_set_flow_ctrl(req_msg, param->flow_control);
 	cm_req_set_starting_psn(req_msg, cpu_to_be32(param->starting_psn));
 	cm_req_set_local_resp_timeout(req_msg,
-				      param->local_cm_response_timeout);
+		min((u8) IB_CM_MAX_TIMEOUT, param->local_cm_response_timeout));
 	cm_req_set_retry_count(req_msg, param->retry_count);
 	req_msg->pkey = param->primary_path->pkey;
 	cm_req_set_path_mtu(req_msg, param->primary_path->mtu);
@@ -999,10 +1005,10 @@ int ib_send_cm_req(struct ib_cm_id *cm_id,
 	}
 	cm_id->service_id = param->service_id;
 	cm_id->service_mask = __constant_cpu_to_be64(~0ULL);
-	cm_id_priv->timeout_ms = cm_convert_to_ms(
-				    param->primary_path->packet_life_time) * 2 +
-				 cm_convert_to_ms(
-				    param->remote_cm_response_timeout);
+	cm_id_priv->timeout_ms = 
+		min(IB_CM_MAX_TIMEOUT,
+		    cm_convert_to_ms(param->primary_path->packet_life_time) * 2 +
+		    cm_convert_to_ms(param->remote_cm_response_timeout));
 	cm_id_priv->max_cm_retries = param->max_cm_retries;
 	cm_id_priv->initiator_depth = param->initiator_depth;
 	cm_id_priv->responder_resources = param->responder_resources;
@@ -1400,8 +1406,9 @@ static int cm_req_handler(struct cm_work *work)
 		}
 	}
 	cm_id_priv->tid = req_msg->hdr.tid;
-	cm_id_priv->timeout_ms = cm_convert_to_ms(
-					cm_req_get_local_resp_timeout(req_msg));
+	cm_id_priv->timeout_ms =
+		min(IB_CM_MAX_TIMEOUT,
+		    cm_convert_to_ms(cm_req_get_local_resp_timeout(req_msg)));
 	cm_id_priv->max_cm_retries = cm_req_get_max_cm_retries(req_msg);
 	cm_id_priv->remote_qpn = cm_req_get_local_qpn(req_msg);
 	cm_id_priv->initiator_depth = cm_req_get_resp_res(req_msg);
@@ -2303,8 +2310,9 @@ static int cm_mra_handler(struct cm_work *work)
 	work->cm_event.private_data = &mra_msg->private_data;
 	work->cm_event.param.mra_rcvd.service_timeout =
 					cm_mra_get_service_timeout(mra_msg);
-	timeout = cm_convert_to_ms(cm_mra_get_service_timeout(mra_msg)) +
-		  cm_convert_to_ms(cm_id_priv->av.packet_life_time);
+	timeout = min(IB_CM_MAX_TIMEOUT,
+		      cm_convert_to_ms(cm_mra_get_service_timeout(mra_msg)) +
+		      cm_convert_to_ms(cm_id_priv->av.packet_life_time));
 
 	spin_lock_irqsave(&cm_id_priv->lock, flags);
 	switch (cm_id_priv->id.state) {
@@ -2707,7 +2715,7 @@ int ib_send_cm_sidr_req(struct ib_cm_id *cm_id,
 
 	cm_id->service_id = param->service_id;
 	cm_id->service_mask = __constant_cpu_to_be64(~0ULL);
-	cm_id_priv->timeout_ms = param->timeout_ms;
+	cm_id_priv->timeout_ms = min(IB_CM_MAX_TIMEOUT, param->timeout_ms);
 	cm_id_priv->max_cm_retries = param->max_cm_retries;
 	ret = cm_alloc_msg(cm_id_priv, &msg);
 	if (ret)
-- 
1.4.4.3