[PATCH v4 2/4] net/dpaa2: clear active VDQ state when freeing Rx queues

[Hemant Agrawal]

From: Maxime Leroy <maxime at leroys.fr>

When using the prefetch Rx path (dpaa2_dev_prefetch_rx), the driver keeps
track of one outstanding VDQCR command per DPIO portal in the global
rte_global_active_dqs_list[] array. Each queue_storage_info_t also stores
the active result buffer and portal index:

  qs->active_dqs
  qs->active_dpio_id

Before issuing a new pull command, dpaa2_dev_prefetch_rx() checks for an
active entry and spins on qbman_check_command_complete() until the
corresponding VDQCR completes.

On port close / hotplug remove, dpaa2_free_rx_tx_queues() frees all
per-lcore queue_storage_info_t structures and their dq_storage[] buffers,
but never clears the global rte_global_active_dqs_list[] entries. After a
detach/attach sequence (or "del/add" in grout), the prefetch Rx path
still sees an active entry for the portal and spins forever on a stale dq
buffer that has been freed and will never be completed by hardware. In
gdb, dq->dq.tok stays 0 and dpaa2_dev_prefetch_rx() loops in:

  while (!qbman_check_command_complete(get_swp_active_dqs(idx)))
      ;

Fix this by clearing the active VDQ state before freeing queue storage.
For each Rx queue and lcore, if qs->active_dqs is non-NULL, call
clear_swp_active_dqs(qs->active_dpio_id) and set qs->active_dqs to NULL.
Then dpaa2_queue_storage_free() can safely free q_storage and
dq_storage[].

After this change, a DPNI detach/attach sequence no longer leaves stale
entries in rte_global_active_dqs_list[], and the prefetch Rx loop does
not hang waiting for a completion from a previous device instance.

Reproduction:
  - grout:
      grcli interface add  port dpni.1 devargs fslmc:dpni.1
      grcli interface del  dpni.1
      grcli interface add  port dpni.1 devargs fslmc:dpni.1
    -> Rx was stuck in qbman_check_command_complete(), now works.

  - testpmd:
      dpdk-testpmd -n1 -a fslmc:dpni.65535 -- -i --forward-mode=rxonly
      testpmd> port attach fslmc:dpni.1
      testpmd> port start all
      testpmd> start
      testpmd> stop
      testpmd> port stop all
      testpmd> port detach 0
      testpmd> port attach fslmc:dpni.1
      testpmd> port start all
      testpmd> start
    -> Rx was hanging, now runs normal

Fixes: 12d98eceb8ac ("bus/fslmc: enhance QBMAN DQ storage logic")
Cc: jun.yang at nxp.com
Cc: stable at dpdk.org

Signed-off-by: Maxime Leroy <maxime at leroys.fr>
---
 .mailmap                         |  2 +-
 drivers/net/dpaa2/dpaa2_ethdev.c | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/.mailmap b/.mailmap
index 10c37a97a6..d92d4fc24b 100644
--- a/.mailmap
+++ b/.mailmap
@@ -1035,7 +1035,7 @@ Mauricio Vasquez B <mauricio.vasquez at polito.it> <mauricio.vasquezbernal at studenti
 Mauro Annarumma <mauroannarumma at hotmail.it>
 Maxime Coquelin <maxime.coquelin at redhat.com>
 Maxime Gouin <maxime.gouin at 6wind.com>
-Maxime Leroy <maxime.leroy at 6wind.com>
+Maxime Leroy <maxime.leroy at 6wind.com> <maxime at leroys.fr>
 Md Fahad Iqbal Polash <md.fahad.iqbal.polash at intel.com>
 Megha Ajmera <megha.ajmera at intel.com>
 Meijuan Zhao <meijuanx.zhao at intel.com>
diff --git a/drivers/net/dpaa2/dpaa2_ethdev.c b/drivers/net/dpaa2/dpaa2_ethdev.c
index fc63cf4f09..3c3a1508fc 100644
--- a/drivers/net/dpaa2/dpaa2_ethdev.c
+++ b/drivers/net/dpaa2/dpaa2_ethdev.c
@@ -631,6 +631,27 @@ dpaa2_alloc_rx_tx_queues(struct rte_eth_dev *dev)
 	return ret;
 }
 
+static void
+dpaa2_clear_queue_active_dps(struct dpaa2_queue *q, int num_lcores)
+{
+	int i;
+
+	for (i = 0; i < num_lcores; i++) {
+		struct queue_storage_info_t *qs = q->q_storage[i];
+
+		if (!qs)
+			continue;
+
+		if (qs->active_dqs) {
+			while (!qbman_check_command_complete(qs->active_dqs))
+				/* wait */;
+
+			clear_swp_active_dqs(qs->active_dpio_id);
+			qs->active_dqs = NULL;
+		}
+	}
+}
+
 static void
 dpaa2_free_rx_tx_queues(struct rte_eth_dev *dev)
 {
@@ -645,6 +666,8 @@ dpaa2_free_rx_tx_queues(struct rte_eth_dev *dev)
 		/* cleaning up queue storage */
 		for (i = 0; i < priv->nb_rx_queues; i++) {
 			dpaa2_q = priv->rx_vq[i];
+			dpaa2_clear_queue_active_dps(dpaa2_q,
+						RTE_MAX_LCORE);
 			dpaa2_queue_storage_free(dpaa2_q,
 				RTE_MAX_LCORE);
 		}
-- 
2.25.1