Subject: [PATCH net-next v2 04/12] ethtool: make ethtool_ops::cap_rss_ctx_supported optional

From: Jakub Kicinski <[email-masked]>
Date: Fri, 2 Aug 2024 21:26:16 -0700

cap_rss_ctx_supported was created because the API for creating
and configuring additional contexts is mux'ed with the normal
RSS API. Presence of ops does not imply driver can actually
support rss_context != 0 (in fact drivers mostly ignore that
field). cap_rss_ctx_supported lets core check that the driver
is context-aware before calling it.

Now that we have .create_rxfh_context, there is no such
ambiguity. We can depend on presence of the op.
Make setting the bit optional.

Reviewed-by: Joe Damato <[email-masked]>
Signed-off-by: Jakub Kicinski <[email-masked]>
---
 include/linux/ethtool.h | 3 ++-
 net/ethtool/ioctl.c     | 6 ++++--
 net/ethtool/rss.c       | 3 ++-
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 303fda54ef17..55c9f613ab64 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -727,7 +727,8 @@ struct kernel_ethtool_ts_info {
  * @cap_link_lanes_supported: indicates if the driver supports lanes
  *	parameter.
  * @cap_rss_ctx_supported: indicates if the driver supports RSS
- *	contexts.
+ *	contexts via legacy API, drivers implementing @create_rxfh_context
+ *	do not have to set this bit.
  * @cap_rss_sym_xor_supported: indicates if the driver supports symmetric-xor
  *	RSS.
  * @rxfh_indir_space: max size of RSS indirection tables, if indirection table
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 8ca13208d240..52dfb07393a6 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1227,7 +1227,8 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
 	if (rxfh.rsvd8[0] || rxfh.rsvd8[1] || rxfh.rsvd32)
 		return -EINVAL;
 	/* Most drivers don't handle rss_context, check it's 0 as well */
-	if (rxfh.rss_context && !ops->cap_rss_ctx_supported)
+	if (rxfh.rss_context && !(ops->cap_rss_ctx_supported ||
+				  ops->create_rxfh_context))
 		return -EOPNOTSUPP;
 
 	rxfh.indir_size = rxfh_dev.indir_size;
@@ -1357,7 +1358,8 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 	if (rxfh.rsvd8[0] || rxfh.rsvd8[1] || rxfh.rsvd32)
 		return -EINVAL;
 	/* Most drivers don't handle rss_context, check it's 0 as well */
-	if (rxfh.rss_context && !ops->cap_rss_ctx_supported)
+	if (rxfh.rss_context && !(ops->cap_rss_ctx_supported ||
+				  ops->create_rxfh_context))
 		return -EOPNOTSUPP;
 	/* Check input data transformation capabilities */
 	if (rxfh.input_xfrm && rxfh.input_xfrm != RXH_XFRM_SYM_XOR &&
diff --git a/net/ethtool/rss.c b/net/ethtool/rss.c
index 5c4c4505ab9a..a06bdac8b8a2 100644
--- a/net/ethtool/rss.c
+++ b/net/ethtool/rss.c
@@ -60,7 +60,8 @@ rss_prepare_data(const struct ethnl_req_info *req_base,
 		return -EOPNOTSUPP;
 
 	/* Some drivers don't handle rss_context */
-	if (request->rss_context && !ops->cap_rss_ctx_supported)
+	if (request->rss_context && !(ops->cap_rss_ctx_supported ||
+				      ops->create_rxfh_context))
 		return -EOPNOTSUPP;
 
 	ret = ethnl_ops_begin(dev);
-- 
2.45.2