[net-next,2/5] net: ethtool: account for RSS+RXNFC add semantics when checking channel count

Commit Message

[e-mail] Nov. 13, 2024, 12:13 p.m. UTC

From: Edward Cree <[e-mail]>

In ethtool_check_max_channel(), the new RX count must not only cover the
 max queue indices in RSS indirection tables and RXNFC destinations
 separately, but must also, for RXNFC rules with FLOW_RSS, cover the sum
 of the destination queue and the maximum index in the associated RSS
 context's indirection table, since that is the highest queue that the
 rule can actually deliver traffic to.
It could be argued that the max queue across all custom RSS contexts
 (ethtool_get_max_rss_ctx_channel()) need no longer be considered, since
 any context to which packets can actually be delivered will be targeted
 by some RXNFC rule and its max will thus be allowed for by
 ethtool_get_max_rxnfc_channel().  For simplicity we keep both checks, so
 even RSS contexts unused by any RXNFC rule must fit the channel count.

Signed-off-by: Edward Cree <[e-mail]>
---
 net/ethtool/common.c | 42 ++++++++++++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 12 deletions(-)

Patch

diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index 0d62363dbd9d..05ce4f8080b3 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -538,6 +538,20 @@  static int ethtool_get_rxnfc_rule_count(struct net_device *dev)
 	return info.rule_cnt;
 }
 
+/* Max offset for one RSS context */
+static u32 ethtool_get_rss_ctx_max_channel(struct ethtool_rxfh_context *ctx)
+{
+	u32 max_ring = 0;
+	u32 i, *tbl;
+
+	if (WARN_ON_ONCE(!ctx))
+		return 0;
+	tbl = ethtool_rxfh_context_indir(ctx);
+	for (i = 0; i < ctx->indir_size; i++)
+		max_ring = max(max_ring, tbl[i]);
+	return max_ring;
+}
+
 static int ethtool_get_max_rxnfc_channel(struct net_device *dev, u64 *max)
 {
 	const struct ethtool_ops *ops = dev->ethtool_ops;
@@ -574,10 +588,18 @@  static int ethtool_get_max_rxnfc_channel(struct net_device *dev, u64 *max)
 
 		if (rule_info.fs.ring_cookie != RX_CLS_FLOW_DISC &&
 		    rule_info.fs.ring_cookie != RX_CLS_FLOW_WAKE &&
-		    !(rule_info.flow_type & FLOW_RSS) &&
-		    !ethtool_get_flow_spec_ring_vf(rule_info.fs.ring_cookie))
-			max_ring =
-				max_t(u64, max_ring, rule_info.fs.ring_cookie);
+		    !ethtool_get_flow_spec_ring_vf(rule_info.fs.ring_cookie)) {
+			u64 ring = rule_info.fs.ring_cookie;
+
+			if (rule_info.flow_type & FLOW_RSS) {
+				struct ethtool_rxfh_context *ctx;
+
+				ctx = xa_load(&dev->ethtool->rss_ctx,
+					      rule_info.rss_context);
+				ring += ethtool_get_rss_ctx_max_channel(ctx);
+			}
+			max_ring = max_t(u64, max_ring, ring);
+		}
 	}
 
 	kvfree(info);
@@ -589,6 +611,7 @@  static int ethtool_get_max_rxnfc_channel(struct net_device *dev, u64 *max)
 	return err;
 }
 
+/* Max offset across all of a device's RSS contexts */
 static u32 ethtool_get_max_rss_ctx_channel(struct net_device *dev)
 {
 	struct ethtool_rxfh_context *ctx;
@@ -596,13 +619,8 @@  static u32 ethtool_get_max_rss_ctx_channel(struct net_device *dev)
 	u32 max_ring = 0;
 
 	mutex_lock(&dev->ethtool->rss_lock);
-	xa_for_each(&dev->ethtool->rss_ctx, context, ctx) {
-		u32 i, *tbl;
-
-		tbl = ethtool_rxfh_context_indir(ctx);
-		for (i = 0; i < ctx->indir_size; i++)
-			max_ring = max(max_ring, tbl[i]);
-	}
+	xa_for_each(&dev->ethtool->rss_ctx, context, ctx)
+		max_ring = max(max_ring, ethtool_get_rss_ctx_max_channel(ctx));
 	mutex_unlock(&dev->ethtool->rss_lock);
 
 	return max_ring;
@@ -611,7 +629,7 @@  static u32 ethtool_get_max_rss_ctx_channel(struct net_device *dev)
 static u32 ethtool_get_max_rxfh_channel(struct net_device *dev)
 {
 	struct ethtool_rxfh_param rxfh = {};
-	u32 dev_size, current_max;
+	u32 dev_size, current_max = 0;
 	int ret;
 
 	/* While we do track whether RSS context has an indirection