[dpdk-dev] [PATCH] net/i40e: fix unexpected mbuf free in vPMD

[Qi Zhang]

vPMD tx does not set sw_ring's mbuf to NULL after free it.
So to prevent same mbuf be free again, we need more carefully
check in i40e_tx_queue_release_mbufs.

Fixes: b4669bb95038 ("i40e: add vector Tx")
Cc: sta...@dpdk.org

Signed-off-by: Qi Zhang <qi.z.zh...@intel.com>
---
v2:
- fix at i40e_tx_queue_release_mbufs so no performance impact.

 drivers/net/i40e/i40e_rxtx.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
index 3a8d32c..f21c1c5 100644
--- a/drivers/net/i40e/i40e_rxtx.c
+++ b/drivers/net/i40e/i40e_rxtx.c
@@ -2305,18 +2305,40 @@ i40e_reset_rx_queue(struct i40e_rx_queue *rxq)
 void
 i40e_tx_queue_release_mbufs(struct i40e_tx_queue *txq)
 {
+       struct rte_eth_dev *dev;
        uint16_t i;
 
+       dev = &rte_eth_devices[txq->port_id];
+
        if (!txq || !txq->sw_ring) {
                PMD_DRV_LOG(DEBUG, "Pointer to rxq or sw_ring is NULL");
                return;
        }
 
-       for (i = 0; i < txq->nb_tx_desc; i++) {
-               if (txq->sw_ring[i].mbuf) {
+       /**
+        *  vPMD tx will not set sw_ring's mbuf to NULL after free,
+        *  so need to free remains more carefully.
+        */
+       if (dev->tx_pkt_burst == i40e_xmit_pkts_vec) {
+               i = txq->tx_next_dd - txq->tx_rs_thresh + 1;
+               if (txq->tx_tail < i) {
+                       for (; i < txq->nb_tx_desc; i++) {
+                               rte_pktmbuf_free_seg(txq->sw_ring[i].mbuf);
+                               txq->sw_ring[i].mbuf = NULL;
+                       }
+                       i = 0;
+               }
+               for (; i < txq->tx_tail; i++) {
                        rte_pktmbuf_free_seg(txq->sw_ring[i].mbuf);
                        txq->sw_ring[i].mbuf = NULL;
                }
+       } else {
+               for (i = 0; i < txq->nb_tx_desc; i++) {
+                       if (txq->sw_ring[i].mbuf) {
+                               rte_pktmbuf_free_seg(txq->sw_ring[i].mbuf);
+                               txq->sw_ring[i].mbuf = NULL;
+                       }
+               }
        }
 }
 
-- 
2.9.5