From 1c5c7c91d300355b5b76c5c396e54f6b35bac28a Mon Sep 17 00:00:00 2001 From: Qi Zhang Date: Sat, 4 May 2019 17:29:37 +0800 Subject: [PATCH] net/i40e: fix Tx threshold setup Tx desc's DD status is not cleaned by NIC automatically after packets have been transmitted until software refill a new packet during next loop. So when tx_free_thresh + tx_rs_thresh > nb_desc, it is possible that an outdated DD status be checked as tx_next_dd, then segment fault happen due to free a NULL mbuf pointer. Then patch fixes this issue by 1. try to adapt tx_rs_thresh to an aggressive tx_free_thresh. 2. queue setup fail when tx_free_thresh + tx_rs_thresh > nb_desc Fixes: 4861cde46116 ("i40e: new poll mode driver") Cc: stable@dpdk.org Signed-off-by: Qi Zhang Acked-by: Beilei Xing --- drivers/net/i40e/i40e_rxtx.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c index 1489552da4..4640a9c661 100644 --- a/drivers/net/i40e/i40e_rxtx.c +++ b/drivers/net/i40e/i40e_rxtx.c @@ -2169,15 +2169,30 @@ i40e_dev_tx_queue_setup(struct rte_eth_dev *dev, * - tx_rs_thresh must be a divisor of the ring size. * - tx_free_thresh must be greater than 0. * - tx_free_thresh must be less than the size of the ring minus 3. + * - tx_free_thresh + tx_rs_thresh must not exceed nb_desc. * * One descriptor in the TX ring is used as a sentinel to avoid a H/W * race condition, hence the maximum threshold constraints. When set * to zero use default values. */ - tx_rs_thresh = (uint16_t)((tx_conf->tx_rs_thresh) ? - tx_conf->tx_rs_thresh : DEFAULT_TX_RS_THRESH); tx_free_thresh = (uint16_t)((tx_conf->tx_free_thresh) ? tx_conf->tx_free_thresh : DEFAULT_TX_FREE_THRESH); + /* force tx_rs_thresh to adapt an aggresive tx_free_thresh */ + tx_rs_thresh = (DEFAULT_TX_RS_THRESH + tx_free_thresh > nb_desc) ? + nb_desc - tx_free_thresh : DEFAULT_TX_RS_THRESH; + if (tx_conf->tx_rs_thresh > 0) + tx_rs_thresh = tx_conf->tx_rs_thresh; + if (tx_rs_thresh + tx_free_thresh > nb_desc) { + PMD_INIT_LOG(ERR, "tx_rs_thresh + tx_free_thresh must not " + "exceed nb_desc. (tx_rs_thresh=%u " + "tx_free_thresh=%u nb_desc=%u port=%d queue=%d)", + (unsigned int)tx_rs_thresh, + (unsigned int)tx_free_thresh, + (unsigned int)nb_desc, + (int)dev->data->port_id, + (int)queue_idx); + return I40E_ERR_PARAM; + } if (tx_rs_thresh >= (nb_desc - 2)) { PMD_INIT_LOG(ERR, "tx_rs_thresh must be less than the " "number of TX descriptors minus 2. " -- 2.20.1