ethtool: set netdev features with FEATURES_SET request

Implement FEATURES_SET netlink request to set network device features.
These are traditionally set using ETHTOOL_SFEATURES ioctl request.

Actual change is subject to netdev_change_features() sanity checks so that
it can differ from what was requested. Unlike with most other SET requests,
in addition to error code and optional extack, kernel provides an optional
reply message (ETHTOOL_MSG_FEATURES_SET_REPLY) in the same format but with
different semantics: information about difference between user request and
actual result and difference between old and new state of dev->features.
This reply message can be suppressed by setting ETHTOOL_FLAG_OMIT_REPLY
flag in request header.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 47 insertions, 9 deletions

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 5713abf98534..d6706c4aa972 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -190,6 +190,7 @@ Userspace to kernel:
   ``ETHTOOL_MSG_WOL_GET``               get wake-on-lan settings
   ``ETHTOOL_MSG_WOL_SET``               set wake-on-lan settings
   ``ETHTOOL_MSG_FEATURES_GET``          get device features
+  ``ETHTOOL_MSG_FEATURES_SET``          set device features
   ===================================== ================================
 
 Kernel to userspace:
@@ -206,6 +207,7 @@ Kernel to userspace:
   ``ETHTOOL_MSG_WOL_GET_REPLY``         wake-on-lan settings
   ``ETHTOOL_MSG_WOL_NTF``               wake-on-lan settings notification
   ``ETHTOOL_MSG_FEATURES_GET_REPLY``    device features
+  ``ETHTOOL_MSG_FEATURES_SET_REPLY``    optional reply to FEATURES_SET
   ===================================== =================================
 
 ``GET`` requests are sent by userspace applications to retrieve device
@@ -554,6 +556,42 @@ provide all names when using verbose bitmap format), the other three use no
 mask (simple bit lists).
 
 
+FEATURES_SET
+============
+
+Request to set netdev features like ``ETHTOOL_SFEATURES`` ioctl request.
+
+Request contents:
+
+  ====================================  ======  ==========================
+  ``ETHTOOL_A_FEATURES_HEADER``         nested  request header
+  ``ETHTOOL_A_FEATURES_WANTED``         bitset  requested features
+  ====================================  ======  ==========================
+
+Kernel response contents:
+
+  ====================================  ======  ==========================
+  ``ETHTOOL_A_FEATURES_HEADER``         nested  reply header
+  ``ETHTOOL_A_FEATURES_WANTED``         bitset  diff wanted vs. result
+  ``ETHTOOL_A_FEATURES_ACTIVE``         bitset  diff old vs. new active
+  ====================================  ======  ==========================
+
+Request constains only one bitset which can be either value/mask pair (request
+to change specific feature bits and leave the rest) or only a value (request
+to set all features to specified set).
+
+As request is subject to netdev_change_features() sanity checks, optional
+kernel reply (can be suppressed by ``ETHTOOL_FLAG_OMIT_REPLY`` flag in request
+header) informs client about the actual result. ``ETHTOOL_A_FEATURES_WANTED``
+reports the difference between client request and actual result: mask consists
+of bits which differ between requested features and result (dev->features
+after the operation), value consists of values of these bits in the request
+(i.e. negated values from resulting features). ``ETHTOOL_A_FEATURES_ACTIVE``
+reports the difference between old and new dev->features: mask consists of
+bits which have changed, values are their values in new dev->features (after
+the operation).
+
+
 Request translation
 ===================
 
@@ -585,30 +623,30 @@ have their netlink replacement yet.
   ``ETHTOOL_GPAUSEPARAM``             n/a
   ``ETHTOOL_SPAUSEPARAM``             n/a
   ``ETHTOOL_GRXCSUM``                 ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_SRXCSUM``                 n/a
+  ``ETHTOOL_SRXCSUM``                 ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GTXCSUM``                 ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_STXCSUM``                 n/a
+  ``ETHTOOL_STXCSUM``                 ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GSG``                     ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_SSG``                     n/a
+  ``ETHTOOL_SSG``                     ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_TEST``                    n/a
   ``ETHTOOL_GSTRINGS``                ``ETHTOOL_MSG_STRSET_GET``
   ``ETHTOOL_PHYS_ID``                 n/a
   ``ETHTOOL_GSTATS``                  n/a
   ``ETHTOOL_GTSO``                    ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_STSO``                    n/a
+  ``ETHTOOL_STSO``                    ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GPERMADDR``               rtnetlink ``RTM_GETLINK``
   ``ETHTOOL_GUFO``                    ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_SUFO``                    n/a
+  ``ETHTOOL_SUFO``                    ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GGSO``                    ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_SGSO``                    n/a
+  ``ETHTOOL_SGSO``                    ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GFLAGS``                  ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_SFLAGS``                  n/a
+  ``ETHTOOL_SFLAGS``                  ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GPFLAGS``                 n/a
   ``ETHTOOL_SPFLAGS``                 n/a
   ``ETHTOOL_GRXFH``                   n/a
   ``ETHTOOL_SRXFH``                   n/a
   ``ETHTOOL_GGRO``                    ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_SGRO``                    n/a
+  ``ETHTOOL_SGRO``                    ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GRXRINGS``                n/a
   ``ETHTOOL_GRXCLSRLCNT``             n/a
   ``ETHTOOL_GRXCLSRULE``              n/a
@@ -623,7 +661,7 @@ have their netlink replacement yet.
   ``ETHTOOL_GRXFHINDIR``              n/a
   ``ETHTOOL_SRXFHINDIR``              n/a
   ``ETHTOOL_GFEATURES``               ``ETHTOOL_MSG_FEATURES_GET``
-  ``ETHTOOL_SFEATURES``               n/a
+  ``ETHTOOL_SFEATURES``               ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GCHANNELS``               n/a
   ``ETHTOOL_SCHANNELS``               n/a
   ``ETHTOOL_SET_DUMP``                n/a