[PATCH v11 07/19] net/pcap: allocate Tx bounce buffer

[Stephen Hemminger]

To handle possible multi segment mbufs, the driver would allocate
a worst case 64k buffer on the stack. Since each Tx queue is
single threaded, better to allocate the buffer from hugepage
with rte_malloc when queue is setup.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 drivers/net/pcap/pcap_ethdev.c | 41 +++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/drivers/net/pcap/pcap_ethdev.c b/drivers/net/pcap/pcap_ethdev.c
index 61ba50e356..1a186142d3 100644
--- a/drivers/net/pcap/pcap_ethdev.c
+++ b/drivers/net/pcap/pcap_ethdev.c
@@ -12,6 +12,7 @@
 #include <errno.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <unistd.h>
 #include <pcap.h>
 
 #include <rte_cycles.h>
@@ -91,6 +92,9 @@ struct pcap_tx_queue {
 	struct queue_stat tx_stat;
 	char name[PATH_MAX];
 	char type[ETH_PCAP_ARG_MAXLEN];
+
+	/* Temp buffer used to for non-linear packets */
+	uint8_t *bounce_buf;
 };
 
 struct pmd_internals {
@@ -392,11 +396,12 @@ eth_pcap_tx_dumper(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	uint32_t tx_bytes = 0;
 	struct pcap_pkthdr header;
 	pcap_dumper_t *dumper;
-	unsigned char temp_data[RTE_ETH_PCAP_SNAPLEN];
+	unsigned char *temp_data;
 	size_t len, caplen;
 
 	pp = rte_eth_devices[dumper_q->port_id].process_private;
 	dumper = pp->tx_dumper[dumper_q->queue_id];
+	temp_data = dumper_q->bounce_buf;
 
 	if (dumper == NULL || nb_pkts == 0)
 		return 0;
@@ -406,10 +411,6 @@ eth_pcap_tx_dumper(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	for (i = 0; i < nb_pkts; i++) {
 		mbuf = bufs[i];
 		len = caplen = rte_pktmbuf_pkt_len(mbuf);
-		if (unlikely(!rte_pktmbuf_is_contiguous(mbuf) &&
-				len > sizeof(temp_data))) {
-			caplen = sizeof(temp_data);
-		}
 
 		calculate_timestamp(&header.ts);
 		header.len = len;
@@ -419,7 +420,7 @@ eth_pcap_tx_dumper(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 		 * a pointer to temp_data after copying into it.
 		 */
 		pcap_dump((u_char *)dumper, &header,
-			rte_pktmbuf_read(mbuf, 0, caplen, temp_data));
+			  rte_pktmbuf_read(mbuf, 0, caplen, temp_data));
 
 		num_tx++;
 		tx_bytes += caplen;
@@ -474,11 +475,12 @@ eth_pcap_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	uint16_t num_tx = 0;
 	uint32_t tx_bytes = 0;
 	pcap_t *pcap;
-	unsigned char temp_data[RTE_ETH_PCAP_SNAPLEN];
+	unsigned char *temp_data;
 	size_t len;
 
 	pp = rte_eth_devices[tx_queue->port_id].process_private;
 	pcap = pp->tx_pcap[tx_queue->queue_id];
+	temp_data = tx_queue->bounce_buf;
 
 	if (unlikely(nb_pkts == 0 || pcap == NULL))
 		return 0;
@@ -486,13 +488,6 @@ eth_pcap_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	for (i = 0; i < nb_pkts; i++) {
 		mbuf = bufs[i];
 		len = rte_pktmbuf_pkt_len(mbuf);
-		if (unlikely(!rte_pktmbuf_is_contiguous(mbuf) &&
-				len > sizeof(temp_data))) {
-			PMD_LOG(ERR,
-				"Dropping multi segment PCAP packet. Size (%zd) > max size (%zd).",
-				len, sizeof(temp_data));
-			continue;
-		}
 
 		/* rte_pktmbuf_read() returns a pointer to the data directly
 		 * in the mbuf (when the mbuf is contiguous) or, otherwise,
@@ -962,7 +957,7 @@ static int
 eth_tx_queue_setup(struct rte_eth_dev *dev,
 		uint16_t tx_queue_id,
 		uint16_t nb_tx_desc __rte_unused,
-		unsigned int socket_id __rte_unused,
+		unsigned int socket_id,
 		const struct rte_eth_txconf *tx_conf __rte_unused)
 {
 	struct pmd_internals *internals = dev->data->dev_private;
@@ -970,11 +965,26 @@ eth_tx_queue_setup(struct rte_eth_dev *dev,
 
 	pcap_q->port_id = dev->data->port_id;
 	pcap_q->queue_id = tx_queue_id;
+	pcap_q->bounce_buf = rte_malloc_socket(NULL, RTE_ETH_PCAP_SNAPSHOT_LEN,
+					       RTE_CACHE_LINE_SIZE, socket_id);
+	if (pcap_q->bounce_buf == NULL)
+		return -ENOMEM;
+
 	dev->data->tx_queues[tx_queue_id] = pcap_q;
 
 	return 0;
 }
 
+static void
+eth_tx_queue_release(struct rte_eth_dev *dev, uint16_t tx_queue_id)
+{
+	struct pmd_internals *internals = dev->data->dev_private;
+	struct pcap_tx_queue *pcap_q = &internals->tx_queue[tx_queue_id];
+
+	rte_free(pcap_q->bounce_buf);
+	pcap_q->bounce_buf = NULL;
+}
+
 static int
 eth_rx_queue_start(struct rte_eth_dev *dev, uint16_t rx_queue_id)
 {
@@ -1015,6 +1025,7 @@ static const struct eth_dev_ops ops = {
 	.dev_infos_get = eth_dev_info,
 	.rx_queue_setup = eth_rx_queue_setup,
 	.tx_queue_setup = eth_tx_queue_setup,
+	.tx_queue_release = eth_tx_queue_release,
 	.rx_queue_start = eth_rx_queue_start,
 	.tx_queue_start = eth_tx_queue_start,
 	.rx_queue_stop = eth_rx_queue_stop,
-- 
2.51.0