[dpdk-dev] [PATCH] net/mlx4: fix drop flow resources not freed

[Moti Haimovsky <motih@mellanox.com>]

This patch fixes the drop-flow resources not being freed when the device
is closed.
Issue can be observed when running testpmd and adding the following rule
more than once:
"flow create 0 ingress pattern eth / end actions drop / end"
then either exiting testpmd using the "quit" command or by running the
command: "port stop all"

Fixes: d3a7e09234e4 ("net/mlx4: allocate drop flow resources on demand")
Cc: stable@dpdk.org

Signed-off-by: Moti Haimovsky <motih@mellanox.com>
---
 drivers/net/mlx4/mlx4_flow.c | 33 +++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/drivers/net/mlx4/mlx4_flow.c b/drivers/net/mlx4/mlx4_flow.c
index fb84060..9e6d8dc 100644
--- a/drivers/net/mlx4/mlx4_flow.c
+++ b/drivers/net/mlx4/mlx4_flow.c
@@ -895,6 +895,30 @@ struct mlx4_drop {
 }
 
 /**
+ * Return the number of active drop flow rules currently present
+ * in the list of flows.
+ * Active flow is defined as a flow associated with an ibv_flow.
+ *
+ * @param priv
+ *   Pointer to private structure.
+ *
+ * @return
+ *   Number of active drop-flows.
+ */
+static int
+drop_refcnt(struct priv *priv)
+{
+	struct rte_flow *flow;
+	int count = 0;
+
+	LIST_FOREACH(flow, &priv->flows, next) {
+		if (flow->drop && flow->ibv_flow)
+			count++;
+	}
+	return count;
+}
+
+/**
  * Get a drop flow rule resources instance.
  *
  * @param priv
@@ -910,9 +934,8 @@ struct mlx4_drop {
 	struct mlx4_drop *drop = priv->drop;
 
 	if (drop) {
-		assert(drop->refcnt);
+		assert(drop_refcnt(priv));
 		assert(drop->priv == priv);
-		++drop->refcnt;
 		return drop;
 	}
 	drop = rte_malloc(__func__, sizeof(*drop), 0);
@@ -955,8 +978,10 @@ struct mlx4_drop {
 static void
 mlx4_drop_put(struct mlx4_drop *drop)
 {
-	assert(drop->refcnt);
-	if (--drop->refcnt)
+	int refcnt = drop_refcnt(drop->priv);
+
+	assert(refcnt >= 0);
+	if (refcnt)
 		return;
 	drop->priv->drop = NULL;
 	claim_zero(ibv_destroy_qp(drop->qp));
-- 
1.8.3.1