Re: [dpdk-dev] [PATCH v6 12/19] net/ngbe: add Rx queue setup and release

[Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>]

On 6/17/21 1:59 PM, Jiawen Wu wrote:
> Setup device Rx queue and release Rx queue.
> 
> Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
> ---
>  drivers/net/ngbe/meson.build   |   1 +
>  drivers/net/ngbe/ngbe_ethdev.c |  37 +++-
>  drivers/net/ngbe/ngbe_ethdev.h |  16 ++
>  drivers/net/ngbe/ngbe_rxtx.c   | 308 +++++++++++++++++++++++++++++++++
>  drivers/net/ngbe/ngbe_rxtx.h   |  96 ++++++++++
>  5 files changed, 457 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/net/ngbe/ngbe_rxtx.c
>  create mode 100644 drivers/net/ngbe/ngbe_rxtx.h
> 
> diff --git a/drivers/net/ngbe/meson.build b/drivers/net/ngbe/meson.build
> index 81173fa7f0..9e75b82f1c 100644
> --- a/drivers/net/ngbe/meson.build
> +++ b/drivers/net/ngbe/meson.build
> @@ -12,6 +12,7 @@ objs = [base_objs]
>  
>  sources = files(
>  	'ngbe_ethdev.c',
> +	'ngbe_rxtx.c',
>  )
>  
>  includes += include_directories('base')
> diff --git a/drivers/net/ngbe/ngbe_ethdev.c b/drivers/net/ngbe/ngbe_ethdev.c
> index c952023e8b..e73606c5f3 100644
> --- a/drivers/net/ngbe/ngbe_ethdev.c
> +++ b/drivers/net/ngbe/ngbe_ethdev.c
> @@ -12,6 +12,7 @@
>  #include "ngbe_logs.h"
>  #include "base/ngbe.h"
>  #include "ngbe_ethdev.h"
> +#include "ngbe_rxtx.h"
>  
>  static int ngbe_dev_close(struct rte_eth_dev *dev);
>  
> @@ -37,6 +38,12 @@ static const struct rte_pci_id pci_id_ngbe_map[] = {
>  	{ .vendor_id = 0, /* sentinel */ },
>  };
>  
> +static const struct rte_eth_desc_lim rx_desc_lim = {
> +	.nb_max = NGBE_RING_DESC_MAX,
> +	.nb_min = NGBE_RING_DESC_MIN,
> +	.nb_align = NGBE_RXD_ALIGN,
> +};
> +
>  static const struct eth_dev_ops ngbe_eth_dev_ops;
>  
>  static inline void
> @@ -241,12 +248,19 @@ static int
>  ngbe_dev_configure(struct rte_eth_dev *dev)
>  {
>  	struct ngbe_interrupt *intr = ngbe_dev_intr(dev);
> +	struct ngbe_adapter *adapter = ngbe_dev_adapter(dev);
>  
>  	PMD_INIT_FUNC_TRACE();
>  
>  	/* set flag to update link status after init */
>  	intr->flags |= NGBE_FLAG_NEED_LINK_UPDATE;
>  
> +	/*
> +	 * Initialize to TRUE. If any of Rx queues doesn't meet the bulk
> +	 * allocation Rx preconditions we will reset it.
> +	 */
> +	adapter->rx_bulk_alloc_allowed = true;
> +
>  	return 0;
>  }
>  
> @@ -266,11 +280,30 @@ ngbe_dev_close(struct rte_eth_dev *dev)
>  static int
>  ngbe_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
>  {
> -	RTE_SET_USED(dev);
> +	struct ngbe_hw *hw = ngbe_dev_hw(dev);
> +
> +	dev_info->max_rx_queues = (uint16_t)hw->mac.max_rx_queues;
> +
> +	dev_info->default_rxconf = (struct rte_eth_rxconf) {
> +		.rx_thresh = {
> +			.pthresh = NGBE_DEFAULT_RX_PTHRESH,
> +			.hthresh = NGBE_DEFAULT_RX_HTHRESH,
> +			.wthresh = NGBE_DEFAULT_RX_WTHRESH,
> +		},
> +		.rx_free_thresh = NGBE_DEFAULT_RX_FREE_THRESH,
> +		.rx_drop_en = 0,
> +		.offloads = 0,
> +	};
> +
> +	dev_info->rx_desc_lim = rx_desc_lim;
>  
>  	dev_info->speed_capa = ETH_LINK_SPEED_1G | ETH_LINK_SPEED_100M |
>  				ETH_LINK_SPEED_10M;
>  
> +	/* Driver-preferred Rx/Tx parameters */
> +	dev_info->default_rxportconf.nb_queues = 1;
> +	dev_info->default_rxportconf.ring_size = 256;
> +
>  	return 0;
>  }
>  
> @@ -570,6 +603,8 @@ static const struct eth_dev_ops ngbe_eth_dev_ops = {
>  	.dev_configure              = ngbe_dev_configure,
>  	.dev_infos_get              = ngbe_dev_info_get,
>  	.link_update                = ngbe_dev_link_update,
> +	.rx_queue_setup             = ngbe_dev_rx_queue_setup,
> +	.rx_queue_release           = ngbe_dev_rx_queue_release,
>  };
>  
>  RTE_PMD_REGISTER_PCI(net_ngbe, rte_ngbe_pmd);
> diff --git a/drivers/net/ngbe/ngbe_ethdev.h b/drivers/net/ngbe/ngbe_ethdev.h
> index b67508a3de..6580d288c8 100644
> --- a/drivers/net/ngbe/ngbe_ethdev.h
> +++ b/drivers/net/ngbe/ngbe_ethdev.h
> @@ -30,6 +30,7 @@ struct ngbe_interrupt {
>  struct ngbe_adapter {
>  	struct ngbe_hw             hw;
>  	struct ngbe_interrupt      intr;
> +	bool rx_bulk_alloc_allowed;

Shouldn't it be aligned as well as above fields?

>  };
>  
>  static inline struct ngbe_adapter *
> @@ -58,6 +59,13 @@ ngbe_dev_intr(struct rte_eth_dev *dev)
>  	return intr;
>  }
>  
> +void ngbe_dev_rx_queue_release(void *rxq);
> +
> +int  ngbe_dev_rx_queue_setup(struct rte_eth_dev *dev, uint16_t rx_queue_id,
> +		uint16_t nb_rx_desc, unsigned int socket_id,
> +		const struct rte_eth_rxconf *rx_conf,
> +		struct rte_mempool *mb_pool);
> +
>  int
>  ngbe_dev_link_update_share(struct rte_eth_dev *dev,
>  		int wait_to_complete);
> @@ -66,4 +74,12 @@ ngbe_dev_link_update_share(struct rte_eth_dev *dev,
>  #define NGBE_LINK_UP_CHECK_TIMEOUT   1000 /* ms */
>  #define NGBE_VMDQ_NUM_UC_MAC         4096 /* Maximum nb. of UC MAC addr. */
>  
> +/*
> + *  Default values for Rx/Tx configuration
> + */
> +#define NGBE_DEFAULT_RX_FREE_THRESH  32
> +#define NGBE_DEFAULT_RX_PTHRESH      8
> +#define NGBE_DEFAULT_RX_HTHRESH      8
> +#define NGBE_DEFAULT_RX_WTHRESH      0
> +
>  #endif /* _NGBE_ETHDEV_H_ */
> diff --git a/drivers/net/ngbe/ngbe_rxtx.c b/drivers/net/ngbe/ngbe_rxtx.c
> new file mode 100644
> index 0000000000..df0b64dc01
> --- /dev/null
> +++ b/drivers/net/ngbe/ngbe_rxtx.c
> @@ -0,0 +1,308 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2018-2020 Beijing WangXun Technology Co., Ltd.
> + * Copyright(c) 2010-2017 Intel Corporation
> + */
> +
> +#include <sys/queue.h>
> +
> +#include <stdint.h>
> +#include <rte_ethdev.h>
> +#include <ethdev_driver.h>
> +#include <rte_malloc.h>
> +
> +#include "ngbe_logs.h"
> +#include "base/ngbe.h"
> +#include "ngbe_ethdev.h"
> +#include "ngbe_rxtx.h"
> +
> +/**
> + * ngbe_free_sc_cluster - free the not-yet-completed scattered cluster
> + *
> + * The "next" pointer of the last segment of (not-yet-completed) RSC clusters
> + * in the sw_sc_ring is not set to NULL but rather points to the next
> + * mbuf of this RSC aggregation (that has not been completed yet and still
> + * resides on the HW ring). So, instead of calling for rte_pktmbuf_free() we
> + * will just free first "nb_segs" segments of the cluster explicitly by calling
> + * an rte_pktmbuf_free_seg().
> + *
> + * @m scattered cluster head
> + */
> +static void __rte_cold
> +ngbe_free_sc_cluster(struct rte_mbuf *m)
> +{
> +	uint16_t i, nb_segs = m->nb_segs;
> +	struct rte_mbuf *next_seg;
> +
> +	for (i = 0; i < nb_segs; i++) {
> +		next_seg = m->next;
> +		rte_pktmbuf_free_seg(m);
> +		m = next_seg;
> +	}
> +}
> +
> +static void __rte_cold
> +ngbe_rx_queue_release_mbufs(struct ngbe_rx_queue *rxq)
> +{
> +	unsigned int i;
> +
> +	if (rxq->sw_ring != NULL) {
> +		for (i = 0; i < rxq->nb_rx_desc; i++) {
> +			if (rxq->sw_ring[i].mbuf != NULL) {
> +				rte_pktmbuf_free_seg(rxq->sw_ring[i].mbuf);
> +				rxq->sw_ring[i].mbuf = NULL;
> +			}
> +		}
> +		if (rxq->rx_nb_avail) {

Compare vs 0 explicitly. However, it looks like that the
check is not required at all. Body may be done unconditionally.

> +			for (i = 0; i < rxq->rx_nb_avail; ++i) {
> +				struct rte_mbuf *mb;
> +
> +				mb = rxq->rx_stage[rxq->rx_next_avail + i];
> +				rte_pktmbuf_free_seg(mb);
> +			}
> +			rxq->rx_nb_avail = 0;
> +		}
> +	}
> +
> +	if (rxq->sw_sc_ring != NULL)
> +		for (i = 0; i < rxq->nb_rx_desc; i++)
> +			if (rxq->sw_sc_ring[i].fbuf) {

Compare vs NULL

> +				ngbe_free_sc_cluster(rxq->sw_sc_ring[i].fbuf);
> +				rxq->sw_sc_ring[i].fbuf = NULL;
> +			}
> +}
> +
> +static void __rte_cold
> +ngbe_rx_queue_release(struct ngbe_rx_queue *rxq)
> +{
> +	if (rxq != NULL) {
> +		ngbe_rx_queue_release_mbufs(rxq);
> +		rte_free(rxq->sw_ring);
> +		rte_free(rxq->sw_sc_ring);
> +		rte_free(rxq);
> +	}
> +}
> +
> +void __rte_cold
> +ngbe_dev_rx_queue_release(void *rxq)
> +{
> +	ngbe_rx_queue_release(rxq);
> +}
> +
> +/*
> + * Check if Rx Burst Bulk Alloc function can be used.
> + * Return
> + *        0: the preconditions are satisfied and the bulk allocation function
> + *           can be used.
> + *  -EINVAL: the preconditions are NOT satisfied and the default Rx burst
> + *           function must be used.
> + */
> +static inline int __rte_cold
> +check_rx_burst_bulk_alloc_preconditions(struct ngbe_rx_queue *rxq)
> +{
> +	int ret = 0;
> +
> +	/*
> +	 * Make sure the following pre-conditions are satisfied:
> +	 *   rxq->rx_free_thresh >= RTE_PMD_NGBE_RX_MAX_BURST
> +	 *   rxq->rx_free_thresh < rxq->nb_rx_desc
> +	 *   (rxq->nb_rx_desc % rxq->rx_free_thresh) == 0
> +	 * Scattered packets are not supported.  This should be checked
> +	 * outside of this function.
> +	 */
> +	if (!(rxq->rx_free_thresh >= RTE_PMD_NGBE_RX_MAX_BURST)) {

Isn't is simpler to read and understand:
rxq->rx_free_thresh < RTE_PMD_NGBE_RX_MAX_BURST

> +		PMD_INIT_LOG(DEBUG, "Rx Burst Bulk Alloc Preconditions: "
> +			     "rxq->rx_free_thresh=%d, "
> +			     "RTE_PMD_NGBE_RX_MAX_BURST=%d",

Do not split format string.

> +			     rxq->rx_free_thresh, RTE_PMD_NGBE_RX_MAX_BURST);
> +		ret = -EINVAL;
> +	} else if (!(rxq->rx_free_thresh < rxq->nb_rx_desc)) {

rxq->rx_free_thresh >= rxq->nb_rx_desc
is simpler to read

> +		PMD_INIT_LOG(DEBUG, "Rx Burst Bulk Alloc Preconditions: "
> +			     "rxq->rx_free_thresh=%d, "
> +			     "rxq->nb_rx_desc=%d",

Do not split format string.

> +			     rxq->rx_free_thresh, rxq->nb_rx_desc);
> +		ret = -EINVAL;
> +	} else if (!((rxq->nb_rx_desc % rxq->rx_free_thresh) == 0)) {

(rxq->nb_rx_desc % rxq->rx_free_thresh) != 0
is easier to read

> +		PMD_INIT_LOG(DEBUG, "Rx Burst Bulk Alloc Preconditions: "
> +			     "rxq->nb_rx_desc=%d, "
> +			     "rxq->rx_free_thresh=%d",
> +			     rxq->nb_rx_desc, rxq->rx_free_thresh);

Do not split format string

> +		ret = -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +/* Reset dynamic ngbe_rx_queue fields back to defaults */
> +static void __rte_cold
> +ngbe_reset_rx_queue(struct ngbe_adapter *adapter, struct ngbe_rx_queue *rxq)
> +{
> +	static const struct ngbe_rx_desc zeroed_desc = {
> +						{{0}, {0} }, {{0}, {0} } };
> +	unsigned int i;
> +	uint16_t len = rxq->nb_rx_desc;
> +
> +	/*
> +	 * By default, the Rx queue setup function allocates enough memory for
> +	 * NGBE_RING_DESC_MAX.  The Rx Burst bulk allocation function requires
> +	 * extra memory at the end of the descriptor ring to be zero'd out.
> +	 */
> +	if (adapter->rx_bulk_alloc_allowed)
> +		/* zero out extra memory */
> +		len += RTE_PMD_NGBE_RX_MAX_BURST;
> +
> +	/*
> +	 * Zero out HW ring memory. Zero out extra memory at the end of
> +	 * the H/W ring so look-ahead logic in Rx Burst bulk alloc function
> +	 * reads extra memory as zeros.
> +	 */
> +	for (i = 0; i < len; i++)
> +		rxq->rx_ring[i] = zeroed_desc;
> +
> +	/*
> +	 * initialize extra software ring entries. Space for these extra
> +	 * entries is always allocated
> +	 */
> +	memset(&rxq->fake_mbuf, 0x0, sizeof(rxq->fake_mbuf));
> +	for (i = rxq->nb_rx_desc; i < len; ++i)
> +		rxq->sw_ring[i].mbuf = &rxq->fake_mbuf;
> +
> +	rxq->rx_nb_avail = 0;
> +	rxq->rx_next_avail = 0;
> +	rxq->rx_free_trigger = (uint16_t)(rxq->rx_free_thresh - 1);
> +	rxq->rx_tail = 0;
> +	rxq->nb_rx_hold = 0;
> +	rxq->pkt_first_seg = NULL;
> +	rxq->pkt_last_seg = NULL;
> +}
> +
> +int __rte_cold
> +ngbe_dev_rx_queue_setup(struct rte_eth_dev *dev,
> +			 uint16_t queue_idx,
> +			 uint16_t nb_desc,
> +			 unsigned int socket_id,
> +			 const struct rte_eth_rxconf *rx_conf,
> +			 struct rte_mempool *mp)
> +{
> +	const struct rte_memzone *rz;
> +	struct ngbe_rx_queue *rxq;
> +	struct ngbe_hw     *hw;
> +	uint16_t len;
> +	struct ngbe_adapter *adapter = ngbe_dev_adapter(dev);
> +
> +	PMD_INIT_FUNC_TRACE();
> +	hw = ngbe_dev_hw(dev);
> +
> +	/*
> +	 * Validate number of receive descriptors.
> +	 * It must not exceed hardware maximum, and must be multiple
> +	 * of NGBE_ALIGN.
> +	 */
> +	if (nb_desc % NGBE_RXD_ALIGN != 0 ||
> +			nb_desc > NGBE_RING_DESC_MAX ||
> +			nb_desc < NGBE_RING_DESC_MIN) {
> +		return -EINVAL;
> +	}

rte_eth_rx_queue_setup cares about it

> +
> +	/* Free memory prior to re-allocation if needed... */
> +	if (dev->data->rx_queues[queue_idx] != NULL) {
> +		ngbe_rx_queue_release(dev->data->rx_queues[queue_idx]);
> +		dev->data->rx_queues[queue_idx] = NULL;
> +	}
> +
> +	/* First allocate the Rx queue data structure */
> +	rxq = rte_zmalloc_socket("ethdev RX queue",
> +				 sizeof(struct ngbe_rx_queue),
> +				 RTE_CACHE_LINE_SIZE, socket_id);
> +	if (rxq == NULL)
> +		return -ENOMEM;
> +	rxq->mb_pool = mp;
> +	rxq->nb_rx_desc = nb_desc;
> +	rxq->rx_free_thresh = rx_conf->rx_free_thresh;
> +	rxq->queue_id = queue_idx;
> +	rxq->reg_idx = queue_idx;
> +	rxq->port_id = dev->data->port_id;
> +	rxq->drop_en = rx_conf->rx_drop_en;
> +	rxq->rx_deferred_start = rx_conf->rx_deferred_start;
> +
> +	/*
> +	 * Allocate Rx ring hardware descriptors. A memzone large enough to
> +	 * handle the maximum ring size is allocated in order to allow for
> +	 * resizing in later calls to the queue setup function.
> +	 */
> +	rz = rte_eth_dma_zone_reserve(dev, "rx_ring", queue_idx,
> +				      RX_RING_SZ, NGBE_ALIGN, socket_id);
> +	if (rz == NULL) {
> +		ngbe_rx_queue_release(rxq);
> +		return -ENOMEM;
> +	}
> +
> +	/*
> +	 * Zero init all the descriptors in the ring.
> +	 */
> +	memset(rz->addr, 0, RX_RING_SZ);
> +
> +	rxq->rdt_reg_addr = NGBE_REG_ADDR(hw, NGBE_RXWP(rxq->reg_idx));
> +	rxq->rdh_reg_addr = NGBE_REG_ADDR(hw, NGBE_RXRP(rxq->reg_idx));
> +
> +	rxq->rx_ring_phys_addr = TMZ_PADDR(rz);
> +	rxq->rx_ring = (struct ngbe_rx_desc *)TMZ_VADDR(rz);
> +
> +	/*
> +	 * Certain constraints must be met in order to use the bulk buffer
> +	 * allocation Rx burst function. If any of Rx queues doesn't meet them
> +	 * the feature should be disabled for the whole port.
> +	 */
> +	if (check_rx_burst_bulk_alloc_preconditions(rxq)) {
> +		PMD_INIT_LOG(DEBUG, "queue[%d] doesn't meet Rx Bulk Alloc "
> +				    "preconditions - canceling the feature for "
> +				    "the whole port[%d]",

Do not split format string.

> +			     rxq->queue_id, rxq->port_id);
> +		adapter->rx_bulk_alloc_allowed = false;
> +	}
> +
> +	/*
> +	 * Allocate software ring. Allow for space at the end of the
> +	 * S/W ring to make sure look-ahead logic in bulk alloc Rx burst
> +	 * function does not access an invalid memory region.
> +	 */
> +	len = nb_desc;
> +	if (adapter->rx_bulk_alloc_allowed)
> +		len += RTE_PMD_NGBE_RX_MAX_BURST;
> +
> +	rxq->sw_ring = rte_zmalloc_socket("rxq->sw_ring",
> +					  sizeof(struct ngbe_rx_entry) * len,
> +					  RTE_CACHE_LINE_SIZE, socket_id);
> +	if (rxq->sw_ring == NULL) {
> +		ngbe_rx_queue_release(rxq);
> +		return -ENOMEM;
> +	}
> +
> +	/*
> +	 * Always allocate even if it's not going to be needed in order to
> +	 * simplify the code.
> +	 *
> +	 * This ring is used in Scattered Rx cases and Scattered Rx may
> +	 * be requested in ngbe_dev_rx_init(), which is called later from
> +	 * dev_start() flow.
> +	 */
> +	rxq->sw_sc_ring =
> +		rte_zmalloc_socket("rxq->sw_sc_ring",
> +				  sizeof(struct ngbe_scattered_rx_entry) * len,
> +				  RTE_CACHE_LINE_SIZE, socket_id);
> +	if (rxq->sw_sc_ring == NULL) {
> +		ngbe_rx_queue_release(rxq);
> +		return -ENOMEM;
> +	}
> +
> +	PMD_INIT_LOG(DEBUG, "sw_ring=%p sw_sc_ring=%p hw_ring=%p "
> +			    "dma_addr=0x%" PRIx64,

Do not split format string.

> +		     rxq->sw_ring, rxq->sw_sc_ring, rxq->rx_ring,
> +		     rxq->rx_ring_phys_addr);
> +
> +	dev->data->rx_queues[queue_idx] = rxq;
> +
> +	ngbe_reset_rx_queue(adapter, rxq);
> +
> +	return 0;
> +}
> +
> diff --git a/drivers/net/ngbe/ngbe_rxtx.h b/drivers/net/ngbe/ngbe_rxtx.h
> new file mode 100644
> index 0000000000..92b9a9fd1b
> --- /dev/null
> +++ b/drivers/net/ngbe/ngbe_rxtx.h
> @@ -0,0 +1,96 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2018-2020 Beijing WangXun Technology Co., Ltd.
> + * Copyright(c) 2010-2017 Intel Corporation
> + */
> +
> +#ifndef _NGBE_RXTX_H_
> +#define _NGBE_RXTX_H_
> +
> +/*****************************************************************************
> + * Receive Descriptor
> + *****************************************************************************/
> +struct ngbe_rx_desc {
> +	struct {
> +		union {
> +			rte_le32_t dw0;
> +			struct {
> +				rte_le16_t pkt;
> +				rte_le16_t hdr;
> +			} lo;
> +		};
> +		union {
> +			rte_le32_t dw1;
> +			struct {
> +				rte_le16_t ipid;
> +				rte_le16_t csum;
> +			} hi;
> +		};
> +	} qw0; /* also as r.pkt_addr */
> +	struct {
> +		union {
> +			rte_le32_t dw2;
> +			struct {
> +				rte_le32_t status;
> +			} lo;
> +		};
> +		union {
> +			rte_le32_t dw3;
> +			struct {
> +				rte_le16_t len;
> +				rte_le16_t tag;
> +			} hi;
> +		};
> +	} qw1; /* also as r.hdr_addr */
> +};
> +
> +#define RTE_PMD_NGBE_RX_MAX_BURST 32
> +
> +#define RX_RING_SZ ((NGBE_RING_DESC_MAX + RTE_PMD_NGBE_RX_MAX_BURST) * \
> +		    sizeof(struct ngbe_rx_desc))
> +
> +
> +/**
> + * Structure associated with each descriptor of the Rx ring of a Rx queue.
> + */
> +struct ngbe_rx_entry {
> +	struct rte_mbuf *mbuf; /**< mbuf associated with Rx descriptor. */
> +};
> +
> +struct ngbe_scattered_rx_entry {
> +	struct rte_mbuf *fbuf; /**< First segment of the fragmented packet. */
> +};
> +
> +/**
> + * Structure associated with each Rx queue.
> + */
> +struct ngbe_rx_queue {
> +	struct rte_mempool  *mb_pool; /**< mbuf pool to populate Rx ring. */
> +	volatile struct ngbe_rx_desc *rx_ring; /**< Rx ring virtual address. */
> +	uint64_t            rx_ring_phys_addr; /**< Rx ring DMA address. */
> +	volatile uint32_t   *rdt_reg_addr; /**< RDT register address. */
> +	volatile uint32_t   *rdh_reg_addr; /**< RDH register address. */
> +	struct ngbe_rx_entry *sw_ring; /**< address of Rx software ring. */
> +	/**< address of scattered Rx software ring. */
> +	struct ngbe_scattered_rx_entry *sw_sc_ring;
> +	struct rte_mbuf *pkt_first_seg; /**< First segment of current packet. */
> +	struct rte_mbuf *pkt_last_seg; /**< Last segment of current packet. */
> +	uint16_t            nb_rx_desc; /**< number of Rx descriptors. */
> +	uint16_t            rx_tail;  /**< current value of RDT register. */
> +	uint16_t            nb_rx_hold; /**< number of held free Rx desc. */
> +	uint16_t rx_nb_avail; /**< nr of staged pkts ready to ret to app */
> +	uint16_t rx_next_avail; /**< idx of next staged pkt to ret to app */
> +	uint16_t rx_free_trigger; /**< triggers rx buffer allocation */
> +	uint16_t            rx_free_thresh; /**< max free Rx desc to hold. */
> +	uint16_t            queue_id; /**< RX queue index. */
> +	uint16_t            reg_idx;  /**< RX queue register index. */
> +	/**< Packet type mask for different NICs. */
> +	uint16_t            port_id;  /**< Device port identifier. */
> +	uint8_t             drop_en;  /**< If not 0, set SRRCTL.Drop_En. */
> +	uint8_t             rx_deferred_start; /**< not in global dev start. */
> +	/** need to alloc dummy mbuf, for wraparound when scanning hw ring */
> +	struct rte_mbuf fake_mbuf;
> +	/** hold packets to return to application */
> +	struct rte_mbuf *rx_stage[RTE_PMD_NGBE_RX_MAX_BURST * 2];
> +};
> +
> +#endif /* _NGBE_RXTX_H_ */
>