[dpdk-dev] [RFC v2 3/5] ethdev: copy ethdev 'burst' API into separate structure

[Konstantin Ananyev <konstantin.ananyev@intel.com>]

Copy public function pointers (rx_pkt_burst(), etc.) and related
pointers to internal data from rte_eth_dev structure into a separate flat
array. We can keep it public to still use inline functions for 'fast' calls
(like rte_eth_rx_burst(), etc.) to avoid/minimize slowdown.
The intention is to make rte_eth_dev and related structures internal.
That should allow future possible changes to core eth_dev strcutures
to be transaprent to the user and help to avoid ABI/API breakages.

Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
---
 lib/ethdev/ethdev_private.c  | 53 ++++++++++++++++++++++++++++++++++++
 lib/ethdev/ethdev_private.h  |  7 +++++
 lib/ethdev/rte_ethdev.c      | 17 ++++++++++++
 lib/ethdev/rte_ethdev_core.h | 45 ++++++++++++++++++++++++++++++
 4 files changed, 122 insertions(+)

diff --git a/lib/ethdev/ethdev_private.c b/lib/ethdev/ethdev_private.c
index 012cf73ca2..a1683da77b 100644
--- a/lib/ethdev/ethdev_private.c
+++ b/lib/ethdev/ethdev_private.c
@@ -174,3 +174,56 @@ rte_eth_devargs_parse_representor_ports(char *str, void *data)
 		RTE_LOG(ERR, EAL, "wrong representor format: %s\n", str);
 	return str == NULL ? -1 : 0;
 }
+
+static uint16_t
+dummy_eth_rx_burst(__rte_unused void *rxq,
+		__rte_unused struct rte_mbuf **rx_pkts,
+		__rte_unused uint16_t nb_pkts)
+{
+	RTE_ETHDEV_LOG(ERR, "rx_pkt_burst for unconfigured port\n");
+	rte_errno = ENOTSUP;
+	return 0;
+}
+
+static uint16_t
+dummy_eth_tx_burst(__rte_unused void *txq,
+		__rte_unused struct rte_mbuf **tx_pkts,
+		__rte_unused uint16_t nb_pkts)
+{
+	RTE_ETHDEV_LOG(ERR, "tx_pkt_burst for unconfigured port\n");
+	rte_errno = ENOTSUP;
+	return 0;
+}
+
+void
+eth_dev_burst_api_reset(struct rte_eth_burst_api *rba)
+{
+	static void *dummy_data[RTE_MAX_QUEUES_PER_PORT];
+	static const struct rte_eth_burst_api dummy_api = {
+		.rx_pkt_burst = dummy_eth_rx_burst,
+		.tx_pkt_burst = dummy_eth_tx_burst,
+		.rxq = {.data = dummy_data, .clbk = dummy_data,},
+		.txq = {.data = dummy_data, .clbk = dummy_data,},
+	};
+
+	*rba = dummy_api;
+}
+
+void
+eth_dev_burst_api_setup(struct rte_eth_burst_api *rba,
+		const struct rte_eth_dev *dev)
+{
+	rba->rx_pkt_burst = dev->rx_pkt_burst;
+	rba->tx_pkt_burst = dev->tx_pkt_burst;
+	rba->tx_pkt_prepare = dev->tx_pkt_prepare;
+	rba->rx_queue_count = dev->rx_queue_count;
+	rba->rx_descriptor_status = dev->rx_descriptor_status;
+	rba->tx_descriptor_status = dev->tx_descriptor_status;
+
+	rba->rxq.data = dev->data->rx_queues;
+	rba->rxq.clbk = (void **)(uintptr_t)dev->post_rx_burst_cbs;
+
+	rba->txq.data = dev->data->tx_queues;
+	rba->txq.clbk = (void **)(uintptr_t)dev->pre_tx_burst_cbs;
+}
+
diff --git a/lib/ethdev/ethdev_private.h b/lib/ethdev/ethdev_private.h
index 9bb0879538..54921f4860 100644
--- a/lib/ethdev/ethdev_private.h
+++ b/lib/ethdev/ethdev_private.h
@@ -30,6 +30,13 @@ eth_find_device(const struct rte_eth_dev *_start, rte_eth_cmp_t cmp,
 /* Parse devargs value for representor parameter. */
 int rte_eth_devargs_parse_representor_ports(char *str, void *data);
 
+/* reset eth 'burst' API to dummy values */
+void eth_dev_burst_api_reset(struct rte_eth_burst_api *rba);
+
+/* setup eth 'burst' API to ethdev values */
+void eth_dev_burst_api_setup(struct rte_eth_burst_api *rba,
+		const struct rte_eth_dev *dev);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index 424bc260fa..5904bb7bae 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -44,6 +44,9 @@
 static const char *MZ_RTE_ETH_DEV_DATA = "rte_eth_dev_data";
 struct rte_eth_dev rte_eth_devices[RTE_MAX_ETHPORTS];
 
+/* public 'fast/burst' API */
+struct rte_eth_burst_api rte_eth_burst_api[RTE_MAX_ETHPORTS];
+
 /* spinlock for eth device callbacks */
 static rte_spinlock_t eth_dev_cb_lock = RTE_SPINLOCK_INITIALIZER;
 
@@ -1788,6 +1791,9 @@ rte_eth_dev_start(uint16_t port_id)
 		(*dev->dev_ops->link_update)(dev, 0);
 	}
 
+	/* expose selection of PMD rx/tx function */
+	eth_dev_burst_api_setup(rte_eth_burst_api + port_id, dev);
+
 	rte_ethdev_trace_start(port_id);
 	return 0;
 }
@@ -1810,6 +1816,9 @@ rte_eth_dev_stop(uint16_t port_id)
 		return 0;
 	}
 
+	/* point rx/tx functions to dummy ones */
+	eth_dev_burst_api_reset(rte_eth_burst_api + port_id);
+
 	dev->data->dev_started = 0;
 	ret = (*dev->dev_ops->dev_stop)(dev);
 	rte_ethdev_trace_stop(port_id, ret);
@@ -4568,6 +4577,14 @@ rte_eth_mirror_rule_reset(uint16_t port_id, uint8_t rule_id)
 	return eth_err(port_id, (*dev->dev_ops->mirror_rule_reset)(dev, rule_id));
 }
 
+RTE_INIT(eth_dev_init_burst_api)
+{
+	uint32_t i;
+
+	for (i = 0; i != RTE_DIM(rte_eth_burst_api); i++)
+		eth_dev_burst_api_reset(rte_eth_burst_api + i);
+}
+
 RTE_INIT(eth_dev_init_cb_lists)
 {
 	uint16_t i;
diff --git a/lib/ethdev/rte_ethdev_core.h b/lib/ethdev/rte_ethdev_core.h
index 00f27c643a..da6de5de43 100644
--- a/lib/ethdev/rte_ethdev_core.h
+++ b/lib/ethdev/rte_ethdev_core.h
@@ -53,6 +53,51 @@ typedef int (*eth_rx_descriptor_status_t)(void *rxq, uint16_t offset);
 typedef int (*eth_tx_descriptor_status_t)(void *txq, uint16_t offset);
 /**< @internal Check the status of a Tx descriptor */
 
+/**
+ * @internal
+ * Structure used to hold opaque pointernals to internal ethdev RX/TXi
+ * queues data.
+ * The main purpose to expose these pointers at all - allow compiler
+ * to fetch this data for 'fast' ethdev inline functions in advance.
+ */
+struct rte_ethdev_qdata {
+	void **data;
+	/**< points to array of internal queue data pointers */
+	void **clbk;
+	/**< points to array of queue callback data pointers */
+};
+
+/**
+ * @internal
+ * 'fast' ethdev funcions and related data are hold in a flat array.
+ * one entry per ethdev.
+ */
+struct rte_eth_burst_api {
+
+	/** first 64B line */
+	eth_rx_burst_t rx_pkt_burst;
+	/**< PMD receive function. */
+	eth_tx_burst_t tx_pkt_burst;
+	/**< PMD transmit function. */
+	eth_tx_prep_t tx_pkt_prepare;
+	/**< PMD transmit prepare function. */
+	eth_rx_queue_count_t rx_queue_count;
+	/**< Get the number of used RX descriptors. */
+	eth_rx_descriptor_status_t rx_descriptor_status;
+	/**< Check the status of a Rx descriptor. */
+	eth_tx_descriptor_status_t tx_descriptor_status;
+	/**< Check the status of a Tx descriptor. */
+	uintptr_t reserved[2];
+
+	/** second 64B line */
+	struct rte_ethdev_qdata rxq;
+	struct rte_ethdev_qdata txq;
+	uintptr_t reserved2[4];
+
+} __rte_cache_aligned;
+
+extern struct rte_eth_burst_api rte_eth_burst_api[RTE_MAX_ETHPORTS];
+
 
 /**
  * @internal
-- 
2.26.3