[dpdk-dev] [PATCH v2 14/29] net/mlx4: generalize flow rule priority support

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

Since both internal and user-defined flow rules are handled by a common
implementation, flow rule priority overlaps are easier to detect. No need
to restrict their use to isolated mode only.

With this patch, only the lowest priority level remains inaccessible to
users outside isolated mode.

Also, the PMD no longer automatically assigns a fixed priority level to
user-defined flow rules, which means collisions between overlapping rules
matching a different number of protocol layers at a given priority level
won't be avoided anymore (e.g. "eth" vs. "eth / ipv4 / udp").

As a reminder, the outcome of overlapping rules for a given priority level
was, and still is, undefined territory according to API documentation.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Acked-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
---
 drivers/net/mlx4/mlx4_flow.c | 34 ++++++++++++++++++----------------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/drivers/net/mlx4/mlx4_flow.c b/drivers/net/mlx4/mlx4_flow.c
index fb38179..e1290a8 100644
--- a/drivers/net/mlx4/mlx4_flow.c
+++ b/drivers/net/mlx4/mlx4_flow.c
@@ -155,7 +155,6 @@ mlx4_flow_create_eth(const struct rte_flow_item *item,
 	unsigned int i;
 
 	++flow->ibv_attr->num_of_specs;
-	flow->ibv_attr->priority = 2;
 	eth = (void *)((uintptr_t)flow->ibv_attr + flow->ibv_attr_size);
 	*eth = (struct ibv_flow_spec_eth) {
 		.type = IBV_FLOW_SPEC_ETH,
@@ -232,7 +231,6 @@ mlx4_flow_create_ipv4(const struct rte_flow_item *item,
 	unsigned int ipv4_size = sizeof(struct ibv_flow_spec_ipv4);
 
 	++flow->ibv_attr->num_of_specs;
-	flow->ibv_attr->priority = 1;
 	ipv4 = (void *)((uintptr_t)flow->ibv_attr + flow->ibv_attr_size);
 	*ipv4 = (struct ibv_flow_spec_ipv4) {
 		.type = IBV_FLOW_SPEC_IPV4,
@@ -277,7 +275,6 @@ mlx4_flow_create_udp(const struct rte_flow_item *item,
 	unsigned int udp_size = sizeof(struct ibv_flow_spec_tcp_udp);
 
 	++flow->ibv_attr->num_of_specs;
-	flow->ibv_attr->priority = 0;
 	udp = (void *)((uintptr_t)flow->ibv_attr + flow->ibv_attr_size);
 	*udp = (struct ibv_flow_spec_tcp_udp) {
 		.type = IBV_FLOW_SPEC_UDP,
@@ -318,7 +315,6 @@ mlx4_flow_create_tcp(const struct rte_flow_item *item,
 	unsigned int tcp_size = sizeof(struct ibv_flow_spec_tcp_udp);
 
 	++flow->ibv_attr->num_of_specs;
-	flow->ibv_attr->priority = 0;
 	tcp = (void *)((uintptr_t)flow->ibv_attr + flow->ibv_attr_size);
 	*tcp = (struct ibv_flow_spec_tcp_udp) {
 		.type = IBV_FLOW_SPEC_TCP,
@@ -581,19 +577,11 @@ mlx4_flow_prepare(struct priv *priv,
 	const struct mlx4_flow_proc_item *proc;
 	struct rte_flow temp = { .ibv_attr_size = sizeof(*temp.ibv_attr) };
 	struct rte_flow *flow = &temp;
-	uint32_t priority_override = 0;
 
 	if (attr->group)
 		return rte_flow_error_set
 			(error, ENOTSUP, RTE_FLOW_ERROR_TYPE_ATTR_GROUP,
 			 NULL, "groups are not supported");
-	if (priv->isolated)
-		priority_override = attr->priority;
-	else if (attr->priority)
-		return rte_flow_error_set
-			(error, ENOTSUP, RTE_FLOW_ERROR_TYPE_ATTR_PRIORITY,
-			 NULL,
-			 "priorities are not supported outside isolated mode");
 	if (attr->priority > MLX4_FLOW_PRIORITY_LAST)
 		return rte_flow_error_set
 			(error, ENOTSUP, RTE_FLOW_ERROR_TYPE_ATTR_PRIORITY,
@@ -659,9 +647,6 @@ mlx4_flow_prepare(struct priv *priv,
 		}
 		flow->ibv_attr_size += proc->dst_sz;
 	}
-	/* Use specified priority level when in isolated mode. */
-	if (priv->isolated && flow != &temp)
-		flow->ibv_attr->priority = priority_override;
 	/* Go over actions list. */
 	for (action = actions; action->type; ++action) {
 		switch (action->type) {
@@ -718,6 +703,7 @@ mlx4_flow_prepare(struct priv *priv,
 		*flow->ibv_attr = (struct ibv_flow_attr){
 			.type = IBV_FLOW_ATTR_NORMAL,
 			.size = sizeof(*flow->ibv_attr),
+			.priority = attr->priority,
 			.port = priv->port,
 		};
 		goto fill;
@@ -854,6 +840,22 @@ mlx4_flow_toggle(struct priv *priv,
 			mlx4_drop_put(priv->drop);
 		return 0;
 	}
+	assert(flow->ibv_attr);
+	if (!flow->internal &&
+	    !priv->isolated &&
+	    flow->ibv_attr->priority == MLX4_FLOW_PRIORITY_LAST) {
+		if (flow->ibv_flow) {
+			claim_zero(ibv_destroy_flow(flow->ibv_flow));
+			flow->ibv_flow = NULL;
+			if (flow->drop)
+				mlx4_drop_put(priv->drop);
+		}
+		err = EACCES;
+		msg = ("priority level "
+		       MLX4_STR_EXPAND(MLX4_FLOW_PRIORITY_LAST)
+		       " is reserved when not in isolated mode");
+		goto error;
+	}
 	if (flow->queue) {
 		struct rxq *rxq = NULL;
 
@@ -883,7 +885,6 @@ mlx4_flow_toggle(struct priv *priv,
 		qp = priv->drop->qp;
 	}
 	assert(qp);
-	assert(flow->ibv_attr);
 	if (flow->ibv_flow)
 		return 0;
 	flow->ibv_flow = ibv_create_flow(qp, flow->ibv_attr);
@@ -1028,6 +1029,7 @@ static int
 mlx4_flow_internal(struct priv *priv, struct rte_flow_error *error)
 {
 	struct rte_flow_attr attr = {
+		.priority = MLX4_FLOW_PRIORITY_LAST,
 		.ingress = 1,
 	};
 	struct rte_flow_item pattern[] = {
-- 
2.1.4