From db433d5f75ab9ab87a1e5fb170b9cb9b50e93469 Mon Sep 17 00:00:00 2001 From: "Wei Hu (Xavier)" Date: Wed, 9 Sep 2020 17:23:38 +0800 Subject: [PATCH] net/hns3: add restriction on setting VF MTU When Rx of scattered packets is off, we have some possibility of using vector Rx process function or simple Rx functions in hns3 PMD driver. If the input MTU is increased and the maximum length of received packets is greater than the length of a buffer for Rx packets, the hardware network engine needs to use multiple BDs and buffers to store these packets. This will cause problems when still using vector Rx process function or simple Rx function to receiving packets. So, when Rx of scattered packets is off and device is started, it is not permitted to increase MTU so that the maximum length of Rx packets is greater than Rx buffer length. Signed-off-by: Chengwen Feng Signed-off-by: Wei Hu (Xavier) --- drivers/net/hns3/hns3_ethdev_vf.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/net/hns3/hns3_ethdev_vf.c b/drivers/net/hns3/hns3_ethdev_vf.c index d7f502442c..037a5be7e0 100644 --- a/drivers/net/hns3/hns3_ethdev_vf.c +++ b/drivers/net/hns3/hns3_ethdev_vf.c @@ -871,6 +871,25 @@ hns3vf_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu) return -EIO; } + /* + * when Rx of scattered packets is off, we have some possibility of + * using vector Rx process function or simple Rx functions in hns3 PMD + * driver. If the input MTU is increased and the maximum length of + * received packets is greater than the length of a buffer for Rx + * packet, the hardware network engine needs to use multiple BDs and + * buffers to store these packets. This will cause problems when still + * using vector Rx process function or simple Rx function to receiving + * packets. So, when Rx of scattered packets is off and device is + * started, it is not permitted to increase MTU so that the maximum + * length of Rx packets is greater than Rx buffer length. + */ + if (dev->data->dev_started && !dev->data->scattered_rx && + frame_size > hw->rx_buf_len) { + hns3_err(hw, "failed to set mtu because current is " + "not scattered rx mode"); + return -EOPNOTSUPP; + } + rte_spinlock_lock(&hw->lock); ret = hns3vf_config_mtu(hw, mtu); if (ret) { -- 2.20.1