Merge branch 'fbnic-support-larger-rx-pages'

Björn Töpel says:

====================
fbnic: Support larger RX pages

This series adds support for large io_uring zero-copy RX buffers to
fbnic.

fbnic hardware consumes receive memory in 4 KiB device pages, while
io_uring may expose a larger software buffer, such as 256 KiB. Track
the device-page geometry per BDQ, represent each large buffer with
consecutive descriptors, and decode completions to the corresponding
offset within the buffer. HPQ keeps its existing PAGE_SIZE geometry.

Larger buffers also reduce pressure on the memory provider. One
provider allocation supplies multiple 4 KiB device pages, so the same
amount of receive memory needs fewer net_iov objects and fewer
allocation, refill, and recycle operations. Hardware descriptor use
remains unchanged.

Ring depth and buffer size must be validated together. An ethtool ring
change can otherwise make an active memory-provider configuration
invalid. Store RX ring depths in netdev_config, stage proposed values
in cfg_pending, and validate the default and each RX queue before
committing the change. Both netlink and ioctl use the same transaction
helpers.

The selftest requests a power-of-two buffer larger than twice the MTU,
checks the reported buffer length, and verifies received data. It does
not assume how packets are placed within the buffer.
====================

Link: https://patch.msgid.link/20260925104417.2325213-1-bjorn@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index c4c9ce038611..c3a41fbd5426 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -1025,7 +1025,9 @@ struct kernel_ethtool_ts_info {
  *	types should be set in @supported_coalesce_params.
  *	Returns a negative error code or zero.
  * @get_ringparam: Report ring sizes
- * @set_ringparam: Set ring sizes.  Returns a negative error code or zero.
+ * @set_ringparam: Set ring sizes. The &struct ethtool_ringparam argument is
+ *	also an output; drivers which normalize requested sizes must update it
+ *	with the applied sizes. Returns a negative error code or zero.
  * @get_pause_stats: Report pause frame statistics. Drivers must not zero
  *	statistics which they don't report. The stats structure is initialized
  *	to ETHTOOL_STAT_NOT_SET indicating driver does not report statistics.