[dpdk-dev] [PATCH v1] ixgbe/vector: add rxd 2^n check to avoid mbuf leak

[Cunming Liang]

The mbuf leak happens when the assigned number of rx descriptor is not power of 2.
As it's presumed on vpmd rx(for rx_tail wrap), adding condition check to prevent it.
The root cause reference code in *_recv_raw_pkts_vec* as below.
"rxq->rx_tail = (uint16_t)(rxq->rx_tail & (rxq->nb_rx_desc - 1));".

Reported-by: Stephen Hemminger <stephen at networkplumber.org>
Signed-off-by: Cunming Liang <cunming.liang at intel.com>
---
 The issue was reported in http://www.dpdk.org/ml/archives/dev/2015-February/014127.html

 lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 51 ++++++++++++++-------------------------
 1 file changed, 18 insertions(+), 33 deletions(-)

diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
index 3059375..9ecf3e5 100644
--- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
+++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
@@ -2257,7 +2257,8 @@ ixgbe_dev_rx_queue_setup(struct rte_eth_dev *dev,
 			     rxq->port_id, rxq->queue_id);
 		dev->rx_pkt_burst = ixgbe_recv_pkts_bulk_alloc;
 #ifdef RTE_IXGBE_INC_VECTOR
-		if (!ixgbe_rx_vec_condition_check(dev)) {
+		if (!ixgbe_rx_vec_condition_check(dev) &&
+		    (rte_is_power_of_2(nb_desc))) {
 			PMD_INIT_LOG(INFO, "Vector rx enabled, please make "
 				     "sure RX burst size no less than 32.");
 			dev->rx_pkt_burst = ixgbe_recv_pkts_vec;
@@ -3639,31 +3640,23 @@ ixgbe_dev_rx_init(struct rte_eth_dev *dev)
 		buf_size = (uint16_t) ((srrctl & IXGBE_SRRCTL_BSIZEPKT_MASK) <<
 				       IXGBE_SRRCTL_BSIZEPKT_SHIFT);
 
-		/* It adds dual VLAN length for supporting dual VLAN */
-		if ((dev->data->dev_conf.rxmode.max_rx_pkt_len +
+		if (dev->data->dev_conf.rxmode.enable_scatter ||
+		    /* It adds dual VLAN length for supporting dual VLAN */
+		    (dev->data->dev_conf.rxmode.max_rx_pkt_len +
 				2 * IXGBE_VLAN_TAG_SIZE) > buf_size){
 			if (!dev->data->scattered_rx)
 				PMD_INIT_LOG(DEBUG, "forcing scatter mode");
 			dev->data->scattered_rx = 1;
 #ifdef RTE_IXGBE_INC_VECTOR
-			dev->rx_pkt_burst = ixgbe_recv_scattered_pkts_vec;
-#else
-			dev->rx_pkt_burst = ixgbe_recv_scattered_pkts;
+			if (rte_is_power_of_2(rxq->nb_rx_desc))
+				dev->rx_pkt_burst =
+					ixgbe_recv_scattered_pkts_vec;
+			else
 #endif
+				dev->rx_pkt_burst = ixgbe_recv_scattered_pkts;
 		}
 	}
 
-	if (dev->data->dev_conf.rxmode.enable_scatter) {
-		if (!dev->data->scattered_rx)
-			PMD_INIT_LOG(DEBUG, "forcing scatter mode");
-#ifdef RTE_IXGBE_INC_VECTOR
-		dev->rx_pkt_burst = ixgbe_recv_scattered_pkts_vec;
-#else
-		dev->rx_pkt_burst = ixgbe_recv_scattered_pkts;
-#endif
-		dev->data->scattered_rx = 1;
-	}
-
 	/*
 	 * Device configured with multiple RX queues.
 	 */
@@ -4156,17 +4149,20 @@ ixgbevf_dev_rx_init(struct rte_eth_dev *dev)
 		buf_size = (uint16_t) ((srrctl & IXGBE_SRRCTL_BSIZEPKT_MASK) <<
 				       IXGBE_SRRCTL_BSIZEPKT_SHIFT);
 
-		/* It adds dual VLAN length for supporting dual VLAN */
-		if ((dev->data->dev_conf.rxmode.max_rx_pkt_len +
+		if (dev->data->dev_conf.rxmode.enable_scatter ||
+		    /* It adds dual VLAN length for supporting dual VLAN */
+		    (dev->data->dev_conf.rxmode.max_rx_pkt_len +
 				2 * IXGBE_VLAN_TAG_SIZE) > buf_size) {
 			if (!dev->data->scattered_rx)
 				PMD_INIT_LOG(DEBUG, "forcing scatter mode");
 			dev->data->scattered_rx = 1;
 #ifdef RTE_IXGBE_INC_VECTOR
-			dev->rx_pkt_burst = ixgbe_recv_scattered_pkts_vec;
-#else
-			dev->rx_pkt_burst = ixgbe_recv_scattered_pkts;
+			if (rte_is_power_of_2(rxq->nb_rx_desc))
+				dev->rx_pkt_burst =
+					ixgbe_recv_scattered_pkts_vec;
+			else
 #endif
+				dev->rx_pkt_burst = ixgbe_recv_scattered_pkts;
 		}
 	}
 
@@ -4184,17 +4180,6 @@ ixgbevf_dev_rx_init(struct rte_eth_dev *dev)
 		IXGBE_PSRTYPE_RQPL_SHIFT;
 	IXGBE_WRITE_REG(hw, IXGBE_VFPSRTYPE, psrtype);
 
-	if (dev->data->dev_conf.rxmode.enable_scatter) {
-		if (!dev->data->scattered_rx)
-			PMD_INIT_LOG(DEBUG, "forcing scatter mode");
-#ifdef RTE_IXGBE_INC_VECTOR
-		dev->rx_pkt_burst = ixgbe_recv_scattered_pkts_vec;
-#else
-		dev->rx_pkt_burst = ixgbe_recv_scattered_pkts;
-#endif
-		dev->data->scattered_rx = 1;
-	}
-
 	return 0;
 }
 
-- 
1.8.1.4