From: Edward Cree <ecree.xilinx@xxxxxxxxx>
Ethtool ntuple filters with FLOW_RSS were originally defined as adding
the base queue ID (ring_cookie) to the value from the indirection table,
so that the same table could distribute over more than one set of queues
when used by different filters.
However, some drivers / hardware ignore the ring_cookie, and simply use
the indirection table entries as queue IDs directly. Thus, for drivers
which have not opted in by setting ethtool_ops.cap_rss_rxnfc_adds to
declare that they support the original (addition) semantics, reject in
ethtool_set_rxnfc any filter which combines FLOW_RSS and a nonzero ring.
(For a ring_cookie of zero, both behaviours are equivalent.)
Set the cap bit in sfc, as it is known to support this feature.
Signed-off-by: Edward Cree <ecree.xilinx@xxxxxxxxx>
---
drivers/net/ethernet/sfc/ef100_ethtool.c | 1 +
drivers/net/ethernet/sfc/ethtool.c | 1 +
include/linux/ethtool.h | 4 ++++
net/ethtool/ioctl.c | 5 +++++
4 files changed, 11 insertions(+)
diff --git a/drivers/net/ethernet/sfc/ef100_ethtool.c b/drivers/net/ethernet/sfc/ef100_ethtool.c
index 5c2551369812..6c3b74000d3b 100644
--- a/drivers/net/ethernet/sfc/ef100_ethtool.c
+++ b/drivers/net/ethernet/sfc/ef100_ethtool.c
@@ -59,6 +59,7 @@ const struct ethtool_ops ef100_ethtool_ops = {
.get_rxfh_indir_size = efx_ethtool_get_rxfh_indir_size,
.get_rxfh_key_size = efx_ethtool_get_rxfh_key_size,
.rxfh_per_ctx_key = true,
+ .cap_rss_rxnfc_adds = true,
.rxfh_priv_size = sizeof(struct efx_rss_context_priv),
.get_rxfh = efx_ethtool_get_rxfh,
.set_rxfh = efx_ethtool_set_rxfh,
diff --git a/drivers/net/ethernet/sfc/ethtool.c b/drivers/net/ethernet/sfc/ethtool.c
index bb1930818beb..83d715544f7f 100644
--- a/drivers/net/ethernet/sfc/ethtool.c
+++ b/drivers/net/ethernet/sfc/ethtool.c
@@ -263,6 +263,7 @@ const struct ethtool_ops efx_ethtool_ops = {
.get_rxfh_indir_size = efx_ethtool_get_rxfh_indir_size,
.get_rxfh_key_size = efx_ethtool_get_rxfh_key_size,
.rxfh_per_ctx_key = true,
+ .cap_rss_rxnfc_adds = true,
.rxfh_priv_size = sizeof(struct efx_rss_context_priv),
.get_rxfh = efx_ethtool_get_rxfh,
.set_rxfh = efx_ethtool_set_rxfh,
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 1199e308c8dd..299280c94d07 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -734,6 +734,9 @@ struct kernel_ethtool_ts_info {
* @rxfh_per_ctx_key: device supports setting different RSS key for each
* additional context. Netlink API should report hfunc, key, and input_xfrm
* for every context, not just context 0.
+ * @cap_rss_rxnfc_adds: device supports nonzero ring_cookie in filters with
+ * %FLOW_RSS flag; the queue ID from the filter is added to the value from
+ * the indirection table to determine the delivery queue.
* @rxfh_indir_space: max size of RSS indirection tables, if indirection table
* size as returned by @get_rxfh_indir_size may change during lifetime
* of the device. Leave as 0 if the table size is constant.
@@ -956,6 +959,7 @@ struct ethtool_ops {
u32 cap_rss_ctx_supported:1;
u32 cap_rss_sym_xor_supported:1;
u32 rxfh_per_ctx_key:1;
+ u32 cap_rss_rxnfc_adds:1;
u32 rxfh_indir_space;
u16 rxfh_key_space;
u16 rxfh_priv_size;
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 7da94e26ced6..d86399bcf223 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -992,6 +992,11 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
if (rc)
return rc;
+ /* Nonzero ring with RSS only makes sense if NIC adds them together */
+ if (info.flow_type & FLOW_RSS && !ops->cap_rss_rxnfc_adds &&
+ ethtool_get_flow_spec_ring(info.fs.ring_cookie))
+ return -EINVAL;
+
if (ops->get_rxfh) {
struct ethtool_rxfh_param rxfh = {};
