ethdev: fix VLAN offloads set if no driver callback

Currently, there is a potential problem that changing the content of
dev->data->dev_conf.rxmode.offloads even when there is no
vlan_offload_set driver callback.

It is a good idea that prevent the side effect and make the API return
success if no change requested. This patch fixes the problem, the detail
information as below:
 - keep possibility to do dummy set even if there is no driver callback
 - do not touch Rx mode offloads in device data before checking the
   driver callback availability
 - ensure that Rx mode offloads are rolled back correctly if driver
   callback returns error

Fixes: 81f9db8ecc2c ("ethdev: add vlan offload support")
Cc: stable@dpdk.org
Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
Signed-off-by: Chunsong Feng <fengchunsong@huawei.com>
Signed-off-by: Min Wang (Jushui) <wangmin3@huawei.com>
Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 42ce177..9d62dc4 100644 (file)
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -3254,53 +3254,53 @@ rte_eth_dev_set_vlan_offload(uint16_t port_id, int offload_mask)
        int mask = 0;
        int cur, org = 0;
        uint64_t orig_offloads;
-       uint64_t *dev_offloads;
+       uint64_t dev_offloads;
 
        RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
        dev = &rte_eth_devices[port_id];
 
        /* save original values in case of failure */
        orig_offloads = dev->data->dev_conf.rxmode.offloads;
-       dev_offloads = &dev->data->dev_conf.rxmode.offloads;
+       dev_offloads = orig_offloads;
 
        /*check which option changed by application*/
        cur = !!(offload_mask & ETH_VLAN_STRIP_OFFLOAD);
-       org = !!(*dev_offloads & DEV_RX_OFFLOAD_VLAN_STRIP);
+       org = !!(dev_offloads & DEV_RX_OFFLOAD_VLAN_STRIP);
        if (cur != org) {
                if (cur)
-                       *dev_offloads |= DEV_RX_OFFLOAD_VLAN_STRIP;
+                       dev_offloads |= DEV_RX_OFFLOAD_VLAN_STRIP;
                else
-                       *dev_offloads &= ~DEV_RX_OFFLOAD_VLAN_STRIP;
+                       dev_offloads &= ~DEV_RX_OFFLOAD_VLAN_STRIP;
                mask |= ETH_VLAN_STRIP_MASK;
        }
 
        cur = !!(offload_mask & ETH_VLAN_FILTER_OFFLOAD);
-       org = !!(*dev_offloads & DEV_RX_OFFLOAD_VLAN_FILTER);
+       org = !!(dev_offloads & DEV_RX_OFFLOAD_VLAN_FILTER);
        if (cur != org) {
                if (cur)
-                       *dev_offloads |= DEV_RX_OFFLOAD_VLAN_FILTER;
+                       dev_offloads |= DEV_RX_OFFLOAD_VLAN_FILTER;
                else
-                       *dev_offloads &= ~DEV_RX_OFFLOAD_VLAN_FILTER;
+                       dev_offloads &= ~DEV_RX_OFFLOAD_VLAN_FILTER;
                mask |= ETH_VLAN_FILTER_MASK;
        }
 
        cur = !!(offload_mask & ETH_VLAN_EXTEND_OFFLOAD);
-       org = !!(*dev_offloads & DEV_RX_OFFLOAD_VLAN_EXTEND);
+       org = !!(dev_offloads & DEV_RX_OFFLOAD_VLAN_EXTEND);
        if (cur != org) {
                if (cur)
-                       *dev_offloads |= DEV_RX_OFFLOAD_VLAN_EXTEND;
+                       dev_offloads |= DEV_RX_OFFLOAD_VLAN_EXTEND;
                else
-                       *dev_offloads &= ~DEV_RX_OFFLOAD_VLAN_EXTEND;
+                       dev_offloads &= ~DEV_RX_OFFLOAD_VLAN_EXTEND;
                mask |= ETH_VLAN_EXTEND_MASK;
        }
 
        cur = !!(offload_mask & ETH_QINQ_STRIP_OFFLOAD);
-       org = !!(*dev_offloads & DEV_RX_OFFLOAD_QINQ_STRIP);
+       org = !!(dev_offloads & DEV_RX_OFFLOAD_QINQ_STRIP);
        if (cur != org) {
                if (cur)
-                       *dev_offloads |= DEV_RX_OFFLOAD_QINQ_STRIP;
+                       dev_offloads |= DEV_RX_OFFLOAD_QINQ_STRIP;
                else
-                       *dev_offloads &= ~DEV_RX_OFFLOAD_QINQ_STRIP;
+                       dev_offloads &= ~DEV_RX_OFFLOAD_QINQ_STRIP;
                mask |= ETH_QINQ_STRIP_MASK;
        }
 
@@ -3309,10 +3309,11 @@ rte_eth_dev_set_vlan_offload(uint16_t port_id, int offload_mask)
                return ret;
 
        RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->vlan_offload_set, -ENOTSUP);
+       dev->data->dev_conf.rxmode.offloads = dev_offloads;
        ret = (*dev->dev_ops->vlan_offload_set)(dev, mask);
        if (ret) {
                /* hit an error restore  original values */
-               *dev_offloads = orig_offloads;
+               dev->data->dev_conf.rxmode.offloads = orig_offloads;
        }
 
        return eth_err(port_id, ret);