net/i40e: fix VLAN stripping in VF

[ upstream commit 95ba3f7 ]

When VF adds VLAN, Linux PF driver enables VLAN stripping by default,
this might have issues if the app configured DEV_RX_OFFLOAD_VLAN_STRIP.

This behavior of the Linux driver causes confusion with the DPDK app
using i40e_pmd. So it is better to reconfigure the vlan_offload, which
checks for DEV_RX_OFFLOAD_VLAN_STRIP flag in the dev_conf and enables or
disables the vlan strip in the PF.

Application cannot use rte_eth_dev_set_vlan_offload() to set
the VLAN_STRIP, as this will only work for the first time when
original and current config mismatch, but for all subsequent call
it will be ignored.

Fixes: 4861cde ("i40e: new poll mode driver")

Signed-off-by: Souvik Dey <sodey@rbbn.com>
Acked-by: Jeff Guo <jia.guo@intel.com>

drivers/net/i40e/i40e_ethdev_vf.c

@@ -1056,8 +1056,18 @@ i40evf_add_vlan(struct rte_eth_dev *dev, uint16_t vlanid)
 	args.out_buffer = vf->aq_resp;
 	args.out_size = I40E_AQ_BUF_SZ;
 	err = i40evf_execute_vf_cmd(dev, &args);
-	if (err)
+	if (err) {
 		PMD_DRV_LOG(ERR, "fail to execute command OP_ADD_VLAN");
+		return err;
+	}
+	/**
+	 * In linux kernel driver on receiving ADD_VLAN it enables
+	 * VLAN_STRIP by default. So reconfigure the vlan_offload
+	 * as it was done by the app earlier.
+	 */
+	err = i40evf_vlan_offload_set(dev, ETH_VLAN_STRIP_MASK);
+	if (err)
+		PMD_DRV_LOG(ERR, "fail to set vlan_strip");
 
 	return err;
 }