[dpdk-dev] [PATCH v2] net/mlx5: fix incorrect index when creating flow

[Bing Zhao]

When creating a flow, usually the creating routine is called in
serial. No parallel execution is supported right now. The same
function will be called only once for a single flow creation.
But there is a special case that the creating routine will be called
nested. If the xmeta feature is enabled and there is FLAG / MARK in
the actions list, some metadata reg copy flow needs to be created
before the original flow is applied to the hardware.
In the flow non-cached mode, resources only for flow creation will
not be saved anymore. The memory space is pre-allocated and reused
for each flow. A global index for each device is used to indicate
the memory address of the resources. If the function is called in a
nested mode, then the index will be reset and make everything get
corrupted.
To solve this, a nested index is introduced to save the position for
the original flow creation. Currently, only one level nested call
of the flow creating routine is supported.

Fixes: 9273a26fe267 ("net/mlx5: separate the flow handle resource")

Signed-off-by: Bing Zhao <bingz at mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at mellanox.com>
---
v2: fix the typo of email address.
---
 drivers/net/mlx5/mlx5.h            |  1 +
 drivers/net/mlx5/mlx5_flow.c       | 38 ++++++++++++++++++++++++++------------
 drivers/net/mlx5/mlx5_flow_dv.c    |  2 +-
 drivers/net/mlx5/mlx5_flow_verbs.c |  2 +-
 4 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
index 396dba7..63503ed 100644
--- a/drivers/net/mlx5/mlx5.h
+++ b/drivers/net/mlx5/mlx5.h
@@ -543,6 +543,7 @@ struct mlx5_priv {
 	struct mlx5_flows ctrl_flows; /* Control flow rules. */
 	void *inter_flows; /* Intermediate resources for flow creation. */
 	int flow_idx; /* Intermediate device flow index. */
+	int flow_nested_idx; /* Intermediate device flow index, nested. */
 	LIST_HEAD(rxq, mlx5_rxq_ctrl) rxqsctrl; /* DPDK Rx queues. */
 	LIST_HEAD(rxqobj, mlx5_rxq_obj) rxqsobj; /* Verbs/DevX Rx queues. */
 	LIST_HEAD(hrxq, mlx5_hrxq) hrxqs; /* Verbs Hash Rx queues. */
diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index 3b358b6..c44bc1f 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -4279,8 +4279,15 @@ flow_list_create(struct rte_eth_dev *dev, struct mlx5_flows *list,
 		buf->entries = 1;
 		buf->entry[0].pattern = (void *)(uintptr_t)items;
 	}
-	/* Reset device flow index to 0. */
-	priv->flow_idx = 0;
+	/*
+	 * Record the start index when there is a nested call. All sub-flows
+	 * need to be translated before another calling.
+	 * No need to use ping-pong buffer to save memory here.
+	 */
+	if (priv->flow_idx) {
+		MLX5_ASSERT(!priv->flow_nested_idx);
+		priv->flow_nested_idx = priv->flow_idx;
+	}
 	for (i = 0; i < buf->entries; ++i) {
 		/*
 		 * The splitter may create multiple dev_flows,
@@ -4340,23 +4347,27 @@ flow_list_create(struct rte_eth_dev *dev, struct mlx5_flows *list,
 	if (list)
 		TAILQ_INSERT_TAIL(list, flow, next);
 	flow_rxq_flags_set(dev, flow);
+	/* Nested flow creation index recovery. */
+	priv->flow_idx = priv->flow_nested_idx;
+	if (priv->flow_nested_idx)
+		priv->flow_nested_idx = 0;
 	return flow;
-error_before_flow:
-	if (hairpin_id)
-		mlx5_flow_id_release(priv->sh->flow_id_pool,
-				     hairpin_id);
-	return NULL;
 error:
 	MLX5_ASSERT(flow);
-	flow_mreg_del_copy_action(dev, flow);
 	ret = rte_errno; /* Save rte_errno before cleanup. */
-	if (flow->hairpin_flow_id)
-		mlx5_flow_id_release(priv->sh->flow_id_pool,
-				     flow->hairpin_flow_id);
-	MLX5_ASSERT(flow);
+	flow_mreg_del_copy_action(dev, flow);
 	flow_drv_destroy(dev, flow);
 	rte_free(flow);
 	rte_errno = ret; /* Restore rte_errno. */
+error_before_flow:
+	ret = rte_errno;
+	if (hairpin_id)
+		mlx5_flow_id_release(priv->sh->flow_id_pool,
+				     hairpin_id);
+	rte_errno = ret;
+	priv->flow_idx = priv->flow_nested_idx;
+	if (priv->flow_nested_idx)
+		priv->flow_nested_idx = 0;
 	return NULL;
 }
 
@@ -4606,6 +4617,9 @@ mlx5_flow_alloc_intermediate(struct rte_eth_dev *dev)
 	if (!priv->inter_flows)
 		priv->inter_flows = rte_calloc(__func__, MLX5_NUM_MAX_DEV_FLOWS,
 					       sizeof(struct mlx5_flow), 0);
+	/* Reset the index. */
+	priv->flow_idx = 0;
+	priv->flow_nested_idx = 0;
 }
 
 /**
diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index b8d03d4..18ea577 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -8021,7 +8021,7 @@ __flow_dv_apply(struct rte_eth_dev *dev, struct rte_flow *flow,
 	int err;
 	int idx;
 
-	for (idx = priv->flow_idx - 1; idx >= 0; idx--) {
+	for (idx = priv->flow_idx - 1; idx >= priv->flow_nested_idx; idx--) {
 		dev_flow = &((struct mlx5_flow *)priv->inter_flows)[idx];
 		dv = &dev_flow->dv;
 		dh = dev_flow->handle;
diff --git a/drivers/net/mlx5/mlx5_flow_verbs.c b/drivers/net/mlx5/mlx5_flow_verbs.c
index eb558fd..6274739 100644
--- a/drivers/net/mlx5/mlx5_flow_verbs.c
+++ b/drivers/net/mlx5/mlx5_flow_verbs.c
@@ -1810,7 +1810,7 @@ flow_verbs_apply(struct rte_eth_dev *dev, struct rte_flow *flow,
 	int err;
 	int idx;
 
-	for (idx = priv->flow_idx - 1; idx >= 0; idx--) {
+	for (idx = priv->flow_idx - 1; idx >= priv->flow_nested_idx; idx--) {
 		dev_flow = &((struct mlx5_flow *)priv->inter_flows)[idx];
 		handle = dev_flow->handle;
 		if (handle->act_flags & MLX5_FLOW_ACTION_DROP) {
-- 
2.5.5