[dpdk-dev] [RFC v2] ether: support deferred queue setup

[dpdk-dev] [RFC v2] ether: support deferred queue setup

[Qi Zhang]

According to exist implementation, rte_eth_[rx|tx]_queue_setup will
always return fail if device is already started(rte_eth_dev_start).

This can't satisfied the usage when application want to deferred setup
part of the queues while keep traffic running on those queues already
be setup.

example:
rte_eth_dev_config(nb_rxq = 2, nb_txq =2)
rte_eth_rx_queue_setup(idx = 0 ...)
rte_eth_rx_queue_setup(idx = 0 ...)
rte_eth_dev_start(...) /* [rx|tx]_burst is ready to start on queue 0 */
rte_eth_rx_queue_setup(idx=1 ...) /* fail*/

Basically this is not a general hardware limitation, because for NIC like
i40e, ixgbe, it is not necessary to stop the whole device before configure
a fresh queue or reconfigure an exist queue with no traffic on it.

The patch add new device capability bit into dev_info, so
rte_eth_[rx|tx]_queue_setup will able to started.

Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
---
 lib/librte_ether/rte_ethdev.c | 40 ++++++++++++++++++++++++++++------------
 lib/librte_ether/rte_ethdev.h |  7 +++++++
 2 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 78bed1a16..58bde40bb 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1425,12 +1425,6 @@ rte_eth_rx_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
 		return -EINVAL;
 	}
 
-	if (dev->data->dev_started) {
-		RTE_PMD_DEBUG_TRACE(
-		    "port %d must be stopped to allow configuration\n", port_id);
-		return -EBUSY;
-	}
-
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -ENOTSUP);
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_setup, -ENOTSUP);
 
@@ -1474,10 +1468,25 @@ rte_eth_rx_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
 		return -EINVAL;
 	}
 
+	if (dev->data->dev_started &&
+		!(dev_info.ext_capa & DEV_DEFERRED_RX_QUEUE_SETUP)) {
+		RTE_PMD_DEBUG_TRACE(
+			"port %d must be stopped to allow rx queue setup\n",
+			port_id);
+		return -EBUSY;
+	}
+
 	rxq = dev->data->rx_queues;
 	if (rxq[rx_queue_id]) {
 		RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_release,
 					-ENOTSUP);
+		if (dev->data->dev_started &&
+			!(dev_info.ext_capa & DEV_DEFERRED_RX_QUEUE_RELEASE)) {
+			RTE_PMD_DEBUG_TRACE(
+			  "port %d must be stopped to allow rx queue release\n",
+			  port_id);
+			return -EBUSY;
+		}
 		(*dev->dev_ops->rx_queue_release)(rxq[rx_queue_id]);
 		rxq[rx_queue_id] = NULL;
 	}
@@ -1573,12 +1582,6 @@ rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
 		return -EINVAL;
 	}
 
-	if (dev->data->dev_started) {
-		RTE_PMD_DEBUG_TRACE(
-		    "port %d must be stopped to allow configuration\n", port_id);
-		return -EBUSY;
-	}
-
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -ENOTSUP);
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_queue_setup, -ENOTSUP);
 
@@ -1596,10 +1599,23 @@ rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
 		return -EINVAL;
 	}
 
+	if (dev->data->dev_started &&
+		!(dev_info.ext_capa & DEV_DEFERRED_TX_QUEUE_SETUP)) {
+		RTE_PMD_DEBUG_TRACE(
+			"port %d must be stopped to allow tx queue setup\n",
+		return -EBUSY;
+	}
+
 	txq = dev->data->tx_queues;
 	if (txq[tx_queue_id]) {
 		RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_queue_release,
 					-ENOTSUP);
+		if (dev->data->dev_started &&
+			!(dev_info.ext_capa & DEV_DEFERRED_TX_QUEUE_RELEASE)) {
+			RTE_PMD_DEBUG_TRACE(
+			  "port %d must be stopped to allow tx queue release\n",
+			return -EBUSY;
+		}
 		(*dev->dev_ops->tx_queue_release)(txq[tx_queue_id]);
 		txq[tx_queue_id] = NULL;
 	}
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index 036153306..75a85859d 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -981,6 +981,12 @@ struct rte_eth_conf {
  */
 #define DEV_TX_OFFLOAD_SECURITY         0x00020000
 
+/** < Deferred queue setup / release capability */
+#define DEV_DEFERRED_RX_QUEUE_SETUP 0x00000001
+#define DEV_DEFERRED_TX_QUEUE_SETUP 0x00000002
+#define DEV_DEFERRED_RX_QUEUE_RELEASE 0x00000004
+#define DEV_DEFERRED_TX_QUEUE_RELEASE 0x00000008
+
 /*
  * If new Tx offload capabilities are defined, they also must be
  * mentioned in rte_tx_offload_names in rte_ethdev.c file.
@@ -1029,6 +1035,7 @@ struct rte_eth_dev_info {
 	/** Configured number of rx/tx queues */
 	uint16_t nb_rx_queues; /**< Number of RX queues. */
 	uint16_t nb_tx_queues; /**< Number of TX queues. */
+	uint64_t ext_capa; /**< extended capability */
 };
 
 /**
-- 
2.13.6