net/ixgbe: add vector Rx parameter check

Under the circumstance that `rx_tail` wrap back to zero
and the advance speed of `rx_tail` is greater than `rxrearm_start`,
`rx_tail` will catch up with `rxrearm_start` and surpass it.
This may cause some mbufs be reused by application.

So we need to make some restrictions to ensure that
 `rx_tail` will not exceed `rxrearm_start`.

e.g.

RDH: 972 RDT: 991 rxrearm_nb: 991 rxrearm_start: 992 rx_tail: 959
RDH: 1004 RDT: 1023 rxrearm_nb: 991 rxrearm_start: 0 rx_tail: 991
RDH: 12 RDT: 31 rxrearm_nb: 991 rxrearm_start: 32 rx_tail: 1023
RDH: 31 RDT: 63 rxrearm_nb: 960 rxrearm_start: 64 rx_tail: 0
RDH: 95 RDT: 95 rxrearm_nb: 1016 rxrearm_start: 96 rx_tail: 88
RDH: 95 RDT: 127 rxrearm_nb: 991 rxrearm_start: 128 rx_tail: 95
...
RDH: 908 RDT: 927 rxrearm_nb: 991 rxrearm_start: 928 rx_tail: 895
RDH: 940 RDT: 959 rxrearm_nb: 991 rxrearm_start: 960 rx_tail: 927
RDH: 980 RDT: 991 rxrearm_nb: 991 rxrearm_start: 992 rx_tail: 959
RDH: 991 RDT: 991 rxrearm_nb: 1026 rxrearm_start: 992 rx_tail: 994

when `rx_tail` catches up with `rxrearm_start`,
2(994 - 992) mbufs be reused by application !

Bugzilla ID: 882
Fixes: 5a3cca342417 ("net/ixgbe: fix vector Rx")
Cc: stable@dpdk.org
Signed-off-by: Bin Zheng <zhengbin.89740@bytedance.com>
Acked-by: Leyi Rong <leyi.rong@intel.com>
Reviewed-by: Haiyue Wang <haiyue.wang@intel.com>
Reviewed-by: Liang Ma <liangma@liangbit.com>

diff --git a/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c b/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c
index c56f76b368b677f06fef8ff69fa74587ffb0ff75..bb34b27168de8ae8edec2628aca9f34e2dea97d7 100644 (file)
--- a/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c
@@ -364,6 +364,17 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
        uint8_t vlan_flags;
        uint16_t udp_p_flag = 0; /* Rx Descriptor UDP header present */
 
+       /*
+        * Under the circumstance that `rx_tail` wrap back to zero
+        * and the advance speed of `rx_tail` is greater than `rxrearm_start`,
+        * `rx_tail` will catch up with `rxrearm_start` and surpass it.
+        * This may cause some mbufs be reused by application.
+        *
+        * So we need to make some restrictions to ensure that
+        * `rx_tail` will not exceed `rxrearm_start`.
+        */
+       nb_pkts = RTE_MIN(nb_pkts, RTE_IXGBE_RXQ_REARM_THRESH);
+
        /* nb_pkts has to be floor-aligned to RTE_IXGBE_DESCS_PER_LOOP */
        nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_IXGBE_DESCS_PER_LOOP);