[PATCH net-next v4 0/8] net: ethtool: add dedicated GRXRINGS driver callbacks

[Breno Leitao]

This patchset introduces a new dedicated ethtool_ops callback,
.get_rx_ring_count, which enables drivers to provide the number of RX
rings directly, improving efficiency and clarity in RX ring queries and
RSS configuration.

Number of drivers implements .get_rxnfc callback just to report the ring
count, so, having a proper callback makes sense and simplify .get_rxnfc
(in some cases remove it completely).

This has been suggested by Jakub, and follow the same idea as RXFH
driver callbacks [1].

This also port virtio_net to this new callback. Once there is consensus
on this approach, I can start moving the drivers to this new callback.

Link: https://lore.kernel.org/all/20250611145949.2674086-1-kuba@xxxxxxxxxx/ [1]

Suggested-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
Tested-by: Lei Yang <leiyang@xxxxxxxxxx>
---
Changes in v4:
- Moved ethtool_get_rx_ring_count() to ethtool/common file (Jakub)
- Keep the check for !ops->get_rxnfc only in ethtool_get_rx_ring_count() (Jakub)
- Link to v3: https://lore.kernel.org/r/20250915-gxrings-v3-0-bfd717dbcaad@xxxxxxxxxx

Changes in v3:
- Make ethtool_get_rx_ring_count() non static and use it in rss_set_prep_indir()
- Check return function of ethtool_get_rx_ring_count() in
  ethtool_get_rx_ring_count() (Jakub)
- Link to v2: https://lore.kernel.org/r/20250912-gxrings-v2-0-3c7a60bbeebf@xxxxxxxxxx

Changes in v2:
- rename get_num_rxrings() to ethtool_get_rx_ring_count() (Jakub)
- initialize struct ethtool_rxnfc() (Jakub)
- Link to v1: https://lore.kernel.org/r/20250909-gxrings-v1-0-634282f06a54@xxxxxxxxxx
---
Changes v1 from RFC:
- Renaming and changing the return type of .get_rxrings() callback (Jakub)
- Add the docstring format for the new callback (Simon)
- Remove the unecessary WARN_ONCE() (Jakub)
- Link to RFC: https://lore.kernel.org/r/20250905-gxrings-v1-0-984fc471f28f@xxxxxxxxxx

---
Breno Leitao (8):
      net: ethtool: pass the num of RX rings directly to ethtool_copy_validate_indir
      net: ethtool: add support for ETHTOOL_GRXRINGS ioctl
      net: ethtool: remove the duplicated handling from ethtool_get_rxrings
      net: ethtool: add get_rx_ring_count callback to optimize RX ring queries
      net: ethtool: update set_rxfh to use ethtool_get_rx_ring_count helper
      net: ethtool: update set_rxfh_indir to use ethtool_get_rx_ring_count helper
      net: ethtool: use the new helper in rss_set_prep_indir()
      net: virtio_net: add get_rxrings ethtool callback for RX ring queries

 drivers/net/virtio_net.c | 15 +++--------
 include/linux/ethtool.h  |  2 ++
 net/ethtool/common.c     | 20 ++++++++++++++
 net/ethtool/common.h     |  2 ++
 net/ethtool/ioctl.c      | 69 +++++++++++++++++++++++++++++++++---------------
 net/ethtool/rss.c        | 15 +++++------
 6 files changed, 82 insertions(+), 41 deletions(-)
---
base-commit: 5e87fdc37f8dc619549d49ba5c951b369ce7c136
change-id: 20250905-gxrings-a2ec22ee2aec

Best regards,
--  
Breno Leitao <leitao@xxxxxxxxxx>