IB/mad: Report number of times a mad was retried

To allow ULPs to tune timeout values and capture retry statistics,
report the number of times that a mad send operation was retried.

For RMPP mads, report the total number of times that the any portion
(send window) of the send operation was retried.

Signed-off-by: Sean Hefty <[email protected]>
Signed-off-by: Roland Dreier <[email protected]>

Author: Sean Hefty

drivers/infiniband/core/mad.c

@@ -1100,7 +1100,9 @@ int ib_post_send_mad(struct ib_mad_send_buf *send_buf,
 		mad_send_wr->tid = ((struct ib_mad_hdr *) send_buf->mad)->tid;
 		/* Timeout will be updated after send completes */
 		mad_send_wr->timeout = msecs_to_jiffies(send_buf->timeout_ms);
-		mad_send_wr->retries = send_buf->retries;
+		mad_send_wr->max_retries = send_buf->retries;
+		mad_send_wr->retries_left = send_buf->retries;
+		send_buf->retries = 0;
 		/* Reference for work request to QP + response */
 		mad_send_wr->refcount = 1 + (mad_send_wr->timeout > 0);
 		mad_send_wr->status = IB_WC_SUCCESS;
@@ -2436,9 +2438,12 @@ static int retry_send(struct ib_mad_send_wr_private *mad_send_wr)
 {
 	int ret;
 
-	if (!mad_send_wr->retries--)
+	if (!mad_send_wr->retries_left)
 		return -ETIMEDOUT;
 
+	mad_send_wr->retries_left--;
+	mad_send_wr->send_buf.retries++;
+
 	mad_send_wr->timeout = msecs_to_jiffies(mad_send_wr->send_buf.timeout_ms);
 
 	if (mad_send_wr->mad_agent_priv->agent.rmpp_version) {

drivers/infiniband/core/mad_priv.h

@@ -131,7 +131,8 @@ struct ib_mad_send_wr_private {
 	struct ib_sge sg_list[IB_MAD_SEND_REQ_MAX_SG];
 	__be64 tid;
 	unsigned long timeout;
-	int retries;
+	int max_retries;
+	int retries_left;
 	int retry;
 	int refcount;
 	enum ib_wc_status status;

drivers/infiniband/core/mad_rmpp.c

@@ -684,7 +684,7 @@ static void process_rmpp_ack(struct ib_mad_agent_private *agent,
 
 	if (seg_num > mad_send_wr->last_ack) {
 		adjust_last_ack(mad_send_wr, seg_num);
-		mad_send_wr->retries = mad_send_wr->send_buf.retries;
+		mad_send_wr->retries_left = mad_send_wr->max_retries;
 	}
 	mad_send_wr->newwin = newwin;
 	if (mad_send_wr->last_ack == mad_send_wr->send_buf.seg_count) {

include/rdma/ib_mad.h

@@ -230,7 +230,9 @@ struct ib_class_port_info
  * @seg_count: The number of RMPP segments allocated for this send.
  * @seg_size: Size of each RMPP segment.
  * @timeout_ms: Time to wait for a response.
- * @retries: Number of times to retry a request for a response.
+ * @retries: Number of times to retry a request for a response.  For MADs
+ *   using RMPP, this applies per window.  On completion, returns the number
+ *   of retries needed to complete the transfer.
  *
  * Users are responsible for initializing the MAD buffer itself, with the
  * exception of any RMPP header.  Additional segment buffer space allocated