[PATCH v6 2/2] net/af_xdp: Refactor af_xdp_tx_zc

[Ariel Otilibili]

Both legs of the loop share the same logic: the common parts are about
reserving and filling both address and length into the description.

This is moved into reserve_and_fill().

Bugzilla ID: 1440
Suggested-by: Maryam Tahhan <mtahhan at redhat.com>
Signed-off-by: Ariel Otilibili <ariel.otilibili at 6wind.com>
---
 drivers/net/af_xdp/rte_eth_af_xdp.c | 62 ++++++++++++++++-------------
 1 file changed, 34 insertions(+), 28 deletions(-)

diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c
index 092bcb73aa0a..840a12dbf508 100644
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -536,6 +536,31 @@ kick_tx(struct pkt_tx_queue *txq, struct xsk_ring_cons *cq)
 		}
 }
 
+static inline struct xdp_desc *
+reserve_and_fill(struct pkt_tx_queue *txq, struct rte_mbuf *mbuf,
+		 struct xsk_umem_info *umem)
+{
+	struct xdp_desc *desc = NULL;
+	uint32_t *idx_tx = NULL;
+	uint64_t addr, offset;
+
+	if (!xsk_ring_prod__reserve(&txq->tx, 1, idx_tx))
+		goto out;
+
+	desc = xsk_ring_prod__tx_desc(&txq->tx, *idx_tx);
+	desc->len = mbuf->pkt_len;
+
+	addr = (uint64_t)mbuf - (uint64_t)umem->buffer
+		- umem->mb_pool->header_size;
+	offset = rte_pktmbuf_mtod(mbuf, uint64_t) - (uint64_t)mbuf
+		+ umem->mb_pool->header_size;
+	offset = offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
+	desc->addr = addr | offset;
+
+out:
+	return desc;
+}
+
 #if defined(XDP_UMEM_UNALIGNED_CHUNK_FLAG)
 static uint16_t
 af_xdp_tx_zc(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
@@ -545,10 +570,8 @@ af_xdp_tx_zc(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	struct rte_mbuf *mbuf;
 	unsigned long tx_bytes = 0;
 	int i;
-	uint32_t idx_tx;
 	uint16_t count = 0;
 	struct xdp_desc *desc;
-	uint64_t addr, offset;
 	struct xsk_ring_cons *cq = &txq->pair->cq;
 	uint32_t free_thresh = cq->size >> 1;
 
@@ -559,21 +582,12 @@ af_xdp_tx_zc(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 		mbuf = bufs[i];
 
 		if (mbuf->pool == umem->mb_pool) {
-			if (!xsk_ring_prod__reserve(&txq->tx, 1, &idx_tx)) {
+			if (!(desc = reserve_and_fill(txq, mbuf, umem))) {
 				kick_tx(txq, cq);
-				if (!xsk_ring_prod__reserve(&txq->tx, 1,
-							    &idx_tx))
+				if (!(desc = reserve_and_fill(txq, mbuf, umem)))
 					goto out;
 			}
-			desc = xsk_ring_prod__tx_desc(&txq->tx, idx_tx);
-			desc->len = mbuf->pkt_len;
-			addr = (uint64_t)mbuf - (uint64_t)umem->buffer -
-					umem->mb_pool->header_size;
-			offset = rte_pktmbuf_mtod(mbuf, uint64_t) -
-					(uint64_t)mbuf +
-					umem->mb_pool->header_size;
-			offset = offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
-			desc->addr = addr | offset;
+
 			tx_bytes += desc->len;
 			count++;
 		} else {
@@ -584,26 +598,18 @@ af_xdp_tx_zc(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 			if (local_mbuf == NULL)
 				goto out;
 
-			if (!xsk_ring_prod__reserve(&txq->tx, 1, &idx_tx)) {
+			if (!(desc = reserve_and_fill(txq, local_mbuf, umem))) {
 				rte_pktmbuf_free(local_mbuf);
 				goto out;
 			}
 
-			desc = xsk_ring_prod__tx_desc(&txq->tx, idx_tx);
-			desc->len = mbuf->pkt_len;
-
-			addr = (uint64_t)local_mbuf - (uint64_t)umem->buffer -
-					umem->mb_pool->header_size;
-			offset = rte_pktmbuf_mtod(local_mbuf, uint64_t) -
-					(uint64_t)local_mbuf +
-					umem->mb_pool->header_size;
-			pkt = xsk_umem__get_data(umem->buffer, addr + offset);
-			offset = offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
-			desc->addr = addr | offset;
+			pkt = xsk_umem__get_data(umem->buffer,
+						 (desc->addr & ~0xFFF)
+						 + (desc->addr & 0xFFF));
 			rte_memcpy(pkt, rte_pktmbuf_mtod(mbuf, void *),
-					desc->len);
-			tx_bytes += desc->len;
+				   desc->len);
 			rte_pktmbuf_free(mbuf);
+			tx_bytes += desc->len;
 			count++;
 		}
 	}
-- 
2.30.2