net: ethtool: use the tracking array for get_rxfh on custom RSS contexts

On 'ethtool -x' with rss_context != 0, instead of calling the driver to
 read the RSS settings for the context, just get the settings from the
 rss_ctx xarray, and return them to the user with no driver involvement.

Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://patch.msgid.link/2d0190fa29638f307ea720f882ebd41f6f867694.1719502240.git.ecree.xilinx@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 939ccd106fe1ca528948a1f1489b6c20a4bbf5d6..d8795ed07ba3c48719ef269dcc8dc7cb51109a75 100644 (file)
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1202,6 +1202,7 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
        const struct ethtool_ops *ops = dev->ethtool_ops;
        struct ethtool_rxfh_param rxfh_dev = {};
        u32 user_indir_size, user_key_size;
+       struct ethtool_rxfh_context *ctx;
        struct ethtool_rxfh rxfh;
        u32 indir_bytes;
        u8 *rss_config;
@@ -1249,11 +1250,26 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
        if (user_key_size)
                rxfh_dev.key = rss_config + indir_bytes;
 
-       rxfh_dev.rss_context = rxfh.rss_context;
-
-       ret = dev->ethtool_ops->get_rxfh(dev, &rxfh_dev);
-       if (ret)
-               goto out;
+       if (rxfh.rss_context) {
+               ctx = xa_load(&dev->ethtool->rss_ctx, rxfh.rss_context);
+               if (!ctx) {
+                       ret = -ENOENT;
+                       goto out;
+               }
+               if (rxfh_dev.indir)
+                       memcpy(rxfh_dev.indir, ethtool_rxfh_context_indir(ctx),
+                              indir_bytes);
+               if (rxfh_dev.key)
+                       memcpy(rxfh_dev.key, ethtool_rxfh_context_key(ctx),
+                              user_key_size);
+               rxfh_dev.hfunc = ctx->hfunc;
+               rxfh_dev.input_xfrm = ctx->input_xfrm;
+               ret = 0;
+       } else {
+               ret = dev->ethtool_ops->get_rxfh(dev, &rxfh_dev);
+               if (ret)
+                       goto out;
+       }
 
        if (copy_to_user(useraddr + offsetof(struct ethtool_rxfh, hfunc),
                         &rxfh_dev.hfunc, sizeof(rxfh.hfunc))) {