[infiniband] Allow for sending MADs via GMA without retransmission

src/include/gpxe/ib_gma.h

 };
 
 extern int ib_gma_request ( struct ib_gma *gma, union ib_mad *mad,
-			    struct ib_address_vector *av );
+			    struct ib_address_vector *av, int retry );
 extern int ib_create_gma ( struct ib_gma *gma, struct ib_device *ibdev,
 			   unsigned long qkey );
 extern void ib_destroy_gma ( struct ib_gma *gma );

src/net/infiniband/ib_gma.c

 };
 
 /**
- * Handle MAD request timer expiry
+ * Transmit MAD request
  *
- * @v timer		Retry timer
- * @v expired		Failure indicator
+ * @v gma		General management agent
+ * @v request		MAD request
+ * @ret rc		Return status code
  */
-static void ib_gma_timer_expired ( struct retry_timer *timer, int expired ) {
-	struct ib_mad_request *request =
-		container_of ( timer, struct ib_mad_request, timer );
-	struct ib_gma *gma = request->gma;
-	struct ib_device *ibdev = gma->ibdev;
+static int ib_gma_send ( struct ib_gma *gma, struct ib_mad_request *request ) {
 	struct io_buffer *iobuf;
 	int rc;
 
-	/* Abandon TID if we have tried too many times */
-	if ( expired ) {
-		DBGC ( gma, "GMA %p abandoning TID %08x%08x\n",
-		       gma, ntohl ( request->mad.hdr.tid[0] ),
-		       ntohl ( request->mad.hdr.tid[1] ) );
-		list_del ( &request->list );
-		free ( request );
-		return;
-	}
-
 	DBGC ( gma, "GMA %p TX TID %08x%08x (%02x,%02x,%02x,%04x)\n",
 	       gma, ntohl ( request->mad.hdr.tid[0] ),
 	       ntohl ( request->mad.hdr.tid[1] ), request->mad.hdr.mgmt_class,
 	       ntohs ( request->mad.hdr.attr_id ) );
 	DBGC2_HDA ( gma, 0, &request->mad, sizeof ( request->mad ) );
 
-	/* Restart retransmission timer */
-	start_timer ( timer );
-
 	/* Construct I/O buffer */
 	iobuf = alloc_iob ( sizeof ( request->mad ) );
 	if ( ! iobuf ) {
 		DBGC ( gma, "GMA %p could not allocate buffer for TID "
 		       "%08x%08x\n", gma, ntohl ( request->mad.hdr.tid[0] ),
 		       ntohl ( request->mad.hdr.tid[1] ) );
-		return;
+		return -ENOMEM;
 	}
 	memcpy ( iob_put ( iobuf, sizeof ( request->mad ) ), &request->mad,
 		 sizeof ( request->mad ) );
 
-	/* Post send request */
-	if ( ( rc = ib_post_send ( ibdev, gma->qp, &request->av,
+	/* Send I/O buffer */
+	if ( ( rc = ib_post_send ( gma->ibdev, gma->qp, &request->av,
 				   iobuf ) ) != 0 ) {
 		DBGC ( gma, "GMA %p could not send TID %08x%08x: %s\n",
 		       gma,  ntohl ( request->mad.hdr.tid[0] ),
 		       ntohl ( request->mad.hdr.tid[1] ), strerror ( rc ) );
 		free_iob ( iobuf );
+		return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Handle MAD request timer expiry
+ *
+ * @v timer		Retry timer
+ * @v expired		Failure indicator
+ */
+static void ib_gma_timer_expired ( struct retry_timer *timer, int expired ) {
+	struct ib_mad_request *request =
+		container_of ( timer, struct ib_mad_request, timer );
+	struct ib_gma *gma = request->gma;
+
+	/* Abandon TID if we have tried too many times */
+	if ( expired ) {
+		DBGC ( gma, "GMA %p abandoning TID %08x%08x\n",
+		       gma, ntohl ( request->mad.hdr.tid[0] ),
+		       ntohl ( request->mad.hdr.tid[1] ) );
+		list_del ( &request->list );
+		free ( request );
 		return;
 	}
+
+	/* Restart retransmission timer */
+	start_timer ( timer );
+
+	/* Resend request */
+	ib_gma_send ( gma, request );
 }
 
 /**
  * @v gma		General management agent
  * @v mad		MAD request
  * @v av		Destination address, or NULL for SM
+ * @v retry		Request should be retried until a response arrives
  * @ret rc		Return status code
  */
 int ib_gma_request ( struct ib_gma *gma, union ib_mad *mad,
-		     struct ib_address_vector *av ) {
+		     struct ib_address_vector *av, int retry ) {
 	struct ib_device *ibdev = gma->ibdev;
 	struct ib_mad_request *request;
 
 		return -ENOMEM;
 	}
 	request->gma = gma;
-	list_add ( &request->list, &gma->requests );
 	request->timer.expired = ib_gma_timer_expired;
 
 	/* Determine address vector */
 	request->mad.hdr.tid[0] = htonl ( IB_GMA_TID_MAGIC );
 	request->mad.hdr.tid[1] = htonl ( ++next_request_tid );
 
-	/* Start timer to initiate transmission */
-	start_timer_nodelay ( &request->timer );
+	/* Send initial request.  Ignore errors; the retry timer will
+	 * take care of those we care about.
+	 */
+	ib_gma_send ( gma, request );
+
+	/* Add to list and start timer if applicable */
+	if ( retry ) {
+		list_add ( &request->list, &gma->requests );
+		start_timer ( &request->timer );
+	} else {
+		free ( request );
+	}
 
 	return 0;
 }

src/net/infiniband/ib_pathrec.c

 		 sizeof ( sa->sa_data.path_record.sgid ) );
 
 	/* Issue path record request */
-	if ( ( rc = ib_gma_request ( &ibdev->gma, &mad, NULL ) ) != 0 ) {
+	if ( ( rc = ib_gma_request ( &ibdev->gma, &mad, NULL, 1 ) ) != 0 ) {
 		DBGC ( ibdev, "IBDEV %p could not get path record: %s\n",
 		       ibdev, strerror ( rc ) );
 		return rc;