On 11/07/2025 4:52, Jakub Kicinski wrote:
Support setting RSS hash function / algo via ethtool Netlink.
Like IOCTL we don't validate that the function is within the
range known to the kernel. The drivers do a pretty good job
validating the inputs, and the IDs are technically "dynamically
queried" rather than part of uAPI.
Only change should be that in Netlink we don't support user
explicitly passing ETH_RSS_HASH_NO_CHANGE (0), if no change
is requested the attribute should be absent.
Makes sense.
quoted hunk ↗ jump to hunk
@@ -487,6 +488,9 @@ ethnl_rss_set_validate(struct ethnl_req_info *req_info, struct genl_info *info)
if (request->rss_context && !ops->create_rxfh_context)
bad_attr = bad_attr ?: tb[ETHTOOL_A_RSS_CONTEXT];
+ if (request->rss_context && !ops->rxfh_per_ctx_key)
+ bad_attr = bad_attr ?: tb[ETHTOOL_A_RSS_HFUNC];
Clever, I expected an 'if (tb[ETHTOOL_A_RSS_HFUNC])'.
quoted hunk ↗ jump to hunk
+
if (bad_attr) {
NL_SET_BAD_ATTR(info->extack, bad_attr);
return -EOPNOTSUPP;@@ -586,6 +590,8 @@ rss_set_ctx_update(struct ethtool_rxfh_context *ctx, struct nlattr **tb,
ethtool_rxfh_context_indir(ctx)[i] = rxfh->indir[i];
ctx->indir_configured = !!nla_len(tb[ETHTOOL_A_RSS_INDIR]);
}
+ if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE)
+ ctx->hfunc = rxfh->hfunc;
}
static int
@@ -617,7 +623,11 @@ ethnl_rss_set(struct ethnl_req_info *req_info, struct genl_info *info)
goto exit_clean_data;
mod |= indir_mod;
- rxfh.hfunc = ETH_RSS_HASH_NO_CHANGE;
+ rxfh.hfunc = data.hfunc;
What is this for?
quoted hunk ↗ jump to hunk
+ ethnl_update_u8(&rxfh.hfunc, tb[ETHTOOL_A_RSS_HFUNC], &mod);
+ if (rxfh.hfunc == data.hfunc)
+ rxfh.hfunc = ETH_RSS_HASH_NO_CHANGE;
I think that this is a distinction that we don't currently make in the
drivers/ioctl flow.
NO_CHANGE was specifically used for cases where the user didn't specify
a parameter, not for cases where the request is equal to the configured one.
mlx5 for example, performs this check internally because it can't rely
on NO_CHANGE for requested == configured.
quoted hunk ↗ jump to hunk
+
rxfh.input_xfrm = RXH_XFRM_NO_CHANGE;
mutex_lock(&dev->ethtool->rss_lock);