[Intel-wired-lan] [PATCH iwl-next v3 1/2] ethtool: treat RXH_GTP_TEID as intrinsically symmetric

[Aleksandr Loktionov]

A GTP tunnel uses the same TEID value in both directions of a flow;
including TEID in the hash input does not break src/dst symmetry.

ethtool_rxfh_config_is_sym() currently rejects any hash field bitmap
that contains bits outside the four paired L3/L4 fields.  This causes
drivers that hash GTP flows on TEID to fail the kernel's preflight
validation in ethtool_check_flow_types(), making it impossible for
those drivers to support symmetric-xor transforms at all.

Strip RXH_GTP_TEID from the bitmap before the paired-field check so
that drivers may honestly report TEID hashing without blocking the
configuration of symmetric transforms.

Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov at intel.com>
---
 net/ethtool/common.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index 5fae329..9a3fd76 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -911,6 +911,9 @@ int ethtool_rxfh_config_is_sym(u64 rxfh)
 {
 	bool sym;
 
+	/* Strip TEID before checking - it carries no src/dst asymmetry */
+	rxfh &= ~(u64)RXH_GTP_TEID;
+
 	sym = rxfh == (rxfh & (RXH_IP_SRC | RXH_IP_DST |
 			       RXH_L4_B_0_1 | RXH_L4_B_2_3));
 	sym &= !!(rxfh & RXH_IP_SRC)   == !!(rxfh & RXH_IP_DST);
-- 
2.52.0