[dpdk-dev] [PATCH v2] Allow -ve frame_overhead values

[alanrobertsonatt at gmail.com]

From: Alan Robertson <ar771e at att.com>

When forwarding traffic across a TDM network the ethernet header will
be replaced with a ML-PPP one thereby reducing the size of the packet.

Signed-off-by: Alan Robertson <alan.robertson at att.com>
---
 lib/librte_sched/rte_sched.c | 14 +++++++++++++-
 lib/librte_sched/rte_sched.h |  5 +++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/lib/librte_sched/rte_sched.c b/lib/librte_sched/rte_sched.c
index ad2f7c6d5..c971fd0d4 100644
--- a/lib/librte_sched/rte_sched.c
+++ b/lib/librte_sched/rte_sched.c
@@ -187,7 +187,7 @@ struct rte_sched_port {
 	uint32_t n_pipes_per_subport;
 	uint32_t rate;
 	uint32_t mtu;
-	uint32_t frame_overhead;
+	int32_t frame_overhead;
 	uint16_t qsize[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE];
 	uint32_t n_pipe_profiles;
 	uint32_t pipe_tc3_rate_max;
@@ -1591,6 +1591,10 @@ grinder_credits_check(struct rte_sched_port *port, uint32_t pos)
 	uint32_t pipe_tc_credits = pipe->tc_credits[tc_index];
 	int enough_credits;
 
+#ifdef RTE_SCHED_DEBUG
+	assert((int)(pkt->pkt_len + port->frame_overhead) > 0);
+#endif /* RTE_SCHED_DEBUG */
+
 	/* Check queue credits */
 	enough_credits = (pkt_len <= subport_tb_credits) &&
 		(pkt_len <= subport_tc_credits) &&
@@ -1629,6 +1633,10 @@ grinder_credits_check(struct rte_sched_port *port, uint32_t pos)
 	uint32_t pipe_tc_ov_credits = pipe_tc_ov_mask1[tc_index];
 	int enough_credits;
 
+#ifdef RTE_SCHED_DEBUG
+	assert((int)(pkt->pkt_len + port->frame_overhead) > 0);
+#endif /* RTE_SCHED_DEBUG */
+
 	/* Check pipe and subport credits */
 	enough_credits = (pkt_len <= subport_tb_credits) &&
 		(pkt_len <= subport_tc_credits) &&
@@ -1663,6 +1671,10 @@ grinder_schedule(struct rte_sched_port *port, uint32_t pos)
 	if (!grinder_credits_check(port, pos))
 		return 0;
 
+#ifdef RTE_SCHED_DEBUG
+	assert((int)(pkt->pkt_len + port->frame_overhead) > 0);
+#endif /* RTE_SCHED_DEBUG */
+
 	/* Advance port time */
 	port->time += pkt_len;
 
diff --git a/lib/librte_sched/rte_sched.h b/lib/librte_sched/rte_sched.h
index 5d2a688dc..3e135c1e5 100644
--- a/lib/librte_sched/rte_sched.h
+++ b/lib/librte_sched/rte_sched.h
@@ -190,8 +190,9 @@ struct rte_sched_port_params {
 	uint32_t mtu;                    /**< Maximum Ethernet frame size
 					  * (measured in bytes).
 					  * Should not include the framing overhead. */
-	uint32_t frame_overhead;         /**< Framing overhead per packet
-					  * (measured in bytes) */
+	int32_t frame_overhead;
+	/**< Framing overhead per packet (measured in bytes).
+	 * Can have negative value. */
 	uint32_t n_subports_per_port;    /**< Number of subports */
 	uint32_t n_pipes_per_subport;    /**< Number of pipes per subport */
 	uint16_t qsize[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE];
-- 
2.11.0