net: ethtool: add ring parameter filtering

While the devmem is running, the tcp-data-split and
hds-thresh configuration should not be changed.
If user tries to change tcp-data-split and threshold value while the
devmem is running, it fails and shows extack message.

Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Link: https://patch.msgid.link/20250114142852.3364986-5-ap420073@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ethtool/rings.c b/net/ethtool/rings.c
index a381913a19f0b83bd3bbd5c10f9654ff8a1b4924..d8cd4e4d776226ada5f48cf2ab094826a45e09fc 100644 (file)
--- a/net/ethtool/rings.c
+++ b/net/ethtool/rings.c
@@ -252,6 +252,19 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info)
                return -EINVAL;
        }
 
+       if (dev_get_min_mp_channel_count(dev)) {
+               if (kernel_ringparam.tcp_data_split !=
+                   ETHTOOL_TCP_DATA_SPLIT_ENABLED) {
+                       NL_SET_ERR_MSG(info->extack,
+                                      "can't disable tcp-data-split while device has memory provider enabled");
+                       return -EINVAL;
+               } else if (kernel_ringparam.hds_thresh) {
+                       NL_SET_ERR_MSG(info->extack,
+                                      "can't set non-zero hds_thresh while device is memory provider enabled");
+                       return -EINVAL;
+               }
+       }
+
        /* ensure new ring parameters are within limits */
        if (ringparam.rx_pending > ringparam.rx_max_pending)
                err_attr = tb[ETHTOOL_A_RINGS_RX];