ethdev: copy fast-path API into separate structure

Copy public function pointers (rx_pkt_burst(), etc.) and related
pointers to internal data from rte_eth_dev structure into a
separate flat array. That array will remain in a public header.
The intention here is to make rte_eth_dev and related structures internal.
That should allow future possible changes to core eth_dev structures
to be transparent to the user and help to avoid ABI/API breakages.
The plan is to keep minimal part of data from rte_eth_dev public,
so we still can use inline functions for fast-path calls
(like rte_eth_rx_burst(), etc.) to avoid/minimize slowdown.
The whole idea beyond this new schema:
1. PMDs keep to setup fast-path function pointers and related data
   inside rte_eth_dev struct in the same way they did it before.
2. Inside rte_eth_dev_start() and inside rte_eth_dev_probing_finish()
   (for secondary process) we call eth_dev_fp_ops_setup, which
   copies these function and data pointers into rte_eth_fp_ops[port_id].
3. Inside rte_eth_dev_stop() and inside rte_eth_dev_release_port()
   we call eth_dev_fp_ops_reset(), which resets rte_eth_fp_ops[port_id]
   into some dummy values.
4. fast-path ethdev API (rte_eth_rx_burst(), etc.) will use that new
   flat array to call PMD specific functions.
That approach should allow us to make rte_eth_devices[] private
without introducing regression and help to avoid changes in drivers code.

Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>
Tested-by: Feifei Wang <feifei.wang2@arm.com>

diff --git a/lib/ethdev/ethdev_private.c b/lib/ethdev/ethdev_private.c
index 012cf73..d810c3a 100644 (file)
--- a/lib/ethdev/ethdev_private.c
+++ b/lib/ethdev/ethdev_private.c
@@ -174,3 +174,55 @@ done:
                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 not ready 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 not ready port\n");
+       rte_errno = ENOTSUP;
+       return 0;
+}
+
+void
+eth_dev_fp_ops_reset(struct rte_eth_fp_ops *fpo)
+{
+       static void *dummy_data[RTE_MAX_QUEUES_PER_PORT];
+       static const struct rte_eth_fp_ops dummy_ops = {
+               .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,},
+       };
+
+       *fpo = dummy_ops;
+}
+
+void
+eth_dev_fp_ops_setup(struct rte_eth_fp_ops *fpo,
+               const struct rte_eth_dev *dev)
+{
+       fpo->rx_pkt_burst = dev->rx_pkt_burst;
+       fpo->tx_pkt_burst = dev->tx_pkt_burst;
+       fpo->tx_pkt_prepare = dev->tx_pkt_prepare;
+       fpo->rx_queue_count = dev->rx_queue_count;
+       fpo->rx_descriptor_status = dev->rx_descriptor_status;
+       fpo->tx_descriptor_status = dev->tx_descriptor_status;
+
+       fpo->rxq.data = dev->data->rx_queues;
+       fpo->rxq.clbk = (void **)(uintptr_t)dev->post_rx_burst_cbs;
+
+       fpo->txq.data = dev->data->tx_queues;
+       fpo->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 3724429..5721be7 100644 (file)
--- a/lib/ethdev/ethdev_private.h
+++ b/lib/ethdev/ethdev_private.h
@@ -26,4 +26,11 @@ 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 fast-path API to dummy values */
+void eth_dev_fp_ops_reset(struct rte_eth_fp_ops *fpo);
+
+/* setup eth fast-path API to ethdev values */
+void eth_dev_fp_ops_setup(struct rte_eth_fp_ops *fpo,
+               const struct rte_eth_dev *dev);
+
 #endif /* _ETH_PRIVATE_H_ */

diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index e446f3b..178f5b8 100644 (file)
--- 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-path API */
+struct rte_eth_fp_ops rte_eth_fp_ops[RTE_MAX_ETHPORTS];
+
 /* spinlock for eth device callbacks */
 static rte_spinlock_t eth_dev_cb_lock = RTE_SPINLOCK_INITIALIZER;
 
@@ -579,6 +582,8 @@ rte_eth_dev_release_port(struct rte_eth_dev *eth_dev)
                rte_eth_dev_callback_process(eth_dev,
                                RTE_ETH_EVENT_DESTROY, NULL);
 
+       eth_dev_fp_ops_reset(rte_eth_fp_ops + eth_dev->data->port_id);
+
        rte_spinlock_lock(&eth_dev_shared_data->ownership_lock);
 
        eth_dev->state = RTE_ETH_DEV_UNUSED;
@@ -1792,6 +1797,9 @@ rte_eth_dev_start(uint16_t port_id)
                (*dev->dev_ops->link_update)(dev, 0);
        }
 
+       /* expose selection of PMD fast-path functions */
+       eth_dev_fp_ops_setup(rte_eth_fp_ops + port_id, dev);
+
        rte_ethdev_trace_start(port_id);
        return 0;
 }
@@ -1814,6 +1822,9 @@ rte_eth_dev_stop(uint16_t port_id)
                return 0;
        }
 
+       /* point fast-path functions to dummy ones */
+       eth_dev_fp_ops_reset(rte_eth_fp_ops + port_id);
+
        dev->data->dev_started = 0;
        ret = (*dev->dev_ops->dev_stop)(dev);
        rte_ethdev_trace_stop(port_id, ret);
@@ -4477,6 +4488,14 @@ int rte_eth_set_queue_rate_limit(uint16_t port_id, uint16_t queue_idx,
                                                        queue_idx, tx_rate));
 }
 
+RTE_INIT(eth_dev_init_fp_ops)
+{
+       uint32_t i;
+
+       for (i = 0; i != RTE_DIM(rte_eth_fp_ops); i++)
+               eth_dev_fp_ops_reset(rte_eth_fp_ops + i);
+}
+
 RTE_INIT(eth_dev_init_cb_lists)
 {
        uint16_t i;
@@ -4645,6 +4664,14 @@ rte_eth_dev_probing_finish(struct rte_eth_dev *dev)
        if (dev == NULL)
                return;
 
+       /*
+        * for secondary process, at that point we expect device
+        * to be already 'usable', so shared data and all function pointers
+        * for fast-path devops have to be setup properly inside rte_eth_dev.
+        */
+       if (rte_eal_process_type() == RTE_PROC_SECONDARY)
+               eth_dev_fp_ops_setup(rte_eth_fp_ops + dev->data->port_id, dev);
+
        rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_NEW, NULL);
 
        dev->state = RTE_ETH_DEV_ATTACHED;

diff --git a/lib/ethdev/rte_ethdev_core.h b/lib/ethdev/rte_ethdev_core.h
index af824ef..df7168c 100644 (file)
--- a/lib/ethdev/rte_ethdev_core.h
+++ b/lib/ethdev/rte_ethdev_core.h
@@ -50,6 +50,65 @@ 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 pointers to internal ethdev Rx/Tx
+ * queues data.
+ * The main purpose to expose these pointers at all - allow compiler
+ * to fetch this data for fast-path ethdev inline functions in advance.
+ */
+struct rte_ethdev_qdata {
+       /** points to array of internal queue data pointers */
+       void **data;
+       /** points to array of queue callback data pointers */
+       void **clbk;
+};
+
+/**
+ * @internal
+ * fast-path ethdev functions and related data are hold in a flat array.
+ * One entry per ethdev.
+ * On 64-bit systems contents of this structure occupy exactly two 64B lines.
+ * On 32-bit systems contents of this structure fits into one 64B line.
+ */
+struct rte_eth_fp_ops {
+
+       /**@{*/
+       /**
+        * Rx fast-path functions and related data.
+        * 64-bit systems: occupies first 64B line
+        */
+       /** PMD receive function. */
+       eth_rx_burst_t rx_pkt_burst;
+       /** Get the number of used RX descriptors. */
+       eth_rx_queue_count_t rx_queue_count;
+       /** Check the status of a Rx descriptor. */
+       eth_rx_descriptor_status_t rx_descriptor_status;
+       /** Rx queues data. */
+       struct rte_ethdev_qdata rxq;
+       uintptr_t reserved1[3];
+       /**@}*/
+
+       /**@{*/
+       /**
+        * Tx fast-path functions and related data.
+        * 64-bit systems: occupies second 64B line
+        */
+       /** PMD transmit function. */
+       eth_tx_burst_t tx_pkt_burst;
+       /** PMD transmit prepare function. */
+       eth_tx_prep_t tx_pkt_prepare;
+       /** Check the status of a Tx descriptor. */
+       eth_tx_descriptor_status_t tx_descriptor_status;
+       /** Tx queues data. */
+       struct rte_ethdev_qdata txq;
+       uintptr_t reserved2[3];
+       /**@}*/
+
+} __rte_cache_aligned;
+
+extern struct rte_eth_fp_ops rte_eth_fp_ops[RTE_MAX_ETHPORTS];
+
 
 /**
  * @internal