This warning is emitted when a driver does not default populate an rss
key when one is not provided from userspace. Some devices do not
support individual rss keys per context. For these devices, it is ok
to leave the key zeroed out in ethtool_rxfh_context. Do not warn on
zeroed key when ethtool_ops.rxfh_per_ctx_key == 0.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---
 net/ethtool/ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 65cfe76dafbe..8c4979b8f4f3 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1504,7 +1504,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 			ret = ops->create_rxfh_context(dev, ctx, &rxfh_dev,
 						       extack);
 			/* Make sure driver populates defaults */
-			WARN_ON_ONCE(!ret && !rxfh_dev.key &&
+			WARN_ON_ONCE(!ret && !rxfh_dev.key && ops->rxfh_per_ctx_key &&
 				     !memchr_inv(ethtool_rxfh_context_key(ctx),
 						 0, ctx->key_size));
 		} else if (rxfh_dev.rss_delete) {
-- 
2.43.5

On Thu, 12 Sep 2024 16:05:30 -0700 Daniel Zahka wrote:
> -			WARN_ON_ONCE(!ret && !rxfh_dev.key &&
> +			WARN_ON_ONCE(!ret && !rxfh_dev.key && ops->rxfh_per_ctx_key &&

wrap at 80 chars, please, make sure you read:
https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
before sending v2
-- 
pw-bot: cr