[dpdk-dev] [PATCH v2] net/pcap: fix infinite Rx with large files

[Ferruh Yigit <ferruh.yigit@intel.com>]

Packet forwarding is not working when infinite Rx feature is used with
large .pcap files that has high number of packets.

The problem is number of allocated mbufs are less than the infinite Rx
ring size, and all mbufs consumed to fill the ring, so there is no mbuf
left for forwarding.

Current logic can not detect that infinite Rx ring is not filled
completely and no more mbufs left, and setup continues which leads
silent fail on packet forwarding.

There isn't much can be done when there is not enough mbuf for the given
.pcap file, so additional checks added to detect the case and fail
explicitly with an error log.

Bugzilla ID: 595
Fixes: a3f5252e5cbd ("net/pcap: enable infinitely Rx a pcap file")
Cc: stable@dpdk.org

Reported-by: Cian Ferriter <cian.ferriter@intel.com>
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Cian Ferriter <cian.ferriter@intel.com>
---
v2:
* Updated log message
---
 drivers/net/pcap/rte_eth_pcap.c | 40 ++++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/drivers/net/pcap/rte_eth_pcap.c b/drivers/net/pcap/rte_eth_pcap.c
index c7751b7ba742..90f5d75ea87f 100644
--- a/drivers/net/pcap/rte_eth_pcap.c
+++ b/drivers/net/pcap/rte_eth_pcap.c
@@ -735,6 +735,17 @@ eth_stats_reset(struct rte_eth_dev *dev)
 	return 0;
 }
 
+static inline void
+infinite_rx_ring_free(struct rte_ring *pkts)
+{
+	struct rte_mbuf *bufs;
+
+	while (!rte_ring_dequeue(pkts, (void **)&bufs))
+		rte_pktmbuf_free(bufs);
+
+	rte_ring_free(pkts);
+}
+
 static int
 eth_dev_close(struct rte_eth_dev *dev)
 {
@@ -753,7 +764,6 @@ eth_dev_close(struct rte_eth_dev *dev)
 	if (internals->infinite_rx) {
 		for (i = 0; i < dev->data->nb_rx_queues; i++) {
 			struct pcap_rx_queue *pcap_q = &internals->rx_queue[i];
-			struct rte_mbuf *pcap_buf;
 
 			/*
 			 * 'pcap_q->pkts' can be NULL if 'eth_dev_close()'
@@ -762,11 +772,7 @@ eth_dev_close(struct rte_eth_dev *dev)
 			if (pcap_q->pkts == NULL)
 				continue;
 
-			while (!rte_ring_dequeue(pcap_q->pkts,
-					(void **)&pcap_buf))
-				rte_pktmbuf_free(pcap_buf);
-
-			rte_ring_free(pcap_q->pkts);
+			infinite_rx_ring_free(pcap_q->pkts);
 		}
 	}
 
@@ -835,21 +841,25 @@ eth_rx_queue_setup(struct rte_eth_dev *dev,
 		while (eth_pcap_rx(pcap_q, bufs, 1)) {
 			/* Check for multiseg mbufs. */
 			if (bufs[0]->nb_segs != 1) {
-				rte_pktmbuf_free(*bufs);
-
-				while (!rte_ring_dequeue(pcap_q->pkts,
-						(void **)bufs))
-					rte_pktmbuf_free(*bufs);
-
-				rte_ring_free(pcap_q->pkts);
-				PMD_LOG(ERR, "Multiseg mbufs are not supported in infinite_rx "
-						"mode.");
+				infinite_rx_ring_free(pcap_q->pkts);
+				PMD_LOG(ERR,
+					"Multiseg mbufs are not supported in infinite_rx mode.");
 				return -EINVAL;
 			}
 
 			rte_ring_enqueue_bulk(pcap_q->pkts,
 					(void * const *)bufs, 1, NULL);
 		}
+
+		if (rte_ring_count(pcap_q->pkts) < pcap_pkt_count) {
+			infinite_rx_ring_free(pcap_q->pkts);
+			PMD_LOG(ERR,
+				"Not enough mbufs to accommodate packets in pcap file. "
+				"At least %" PRIu64 " mbufs per queue is required.",
+				pcap_pkt_count);
+			return -EINVAL;
+		}
+
 		/*
 		 * Reset the stats for this queue since eth_pcap_rx calls above
 		 * didn't result in the application receiving packets.
-- 
2.29.2