Hi!
[ Michael and Pavan, I removed your Tested-by:/Reviewed-by: although
the changes were pretty small. Please re-add if you're still OK with
it. ]
Some NICs (e.g. bnxt) change their RSS indirection table size based on
the queue count, because the hardware table is a shared resource. The
ethtool core locks ctx->indir_size at context creation, so drivers
have to reject channel changes when RSS contexts exist.
This series adds resize helpers and wires them up in bnxt.
Patch 1 adds core helpers:
ethtool_rxfh_can_resize() - read-only validation
ethtool_rxfh_resize() - fold/unfold a raw table in place
ethtool_rxfh_ctxs_can_resize() - validate all non-default contexts
ethtool_rxfh_ctxs_resize() - resize all non-default contexts,
with locking and RSS_NTF notifications
Both ethtool_rxfh_can_resize() and ethtool_rxfh_resize() now take a
user_size parameter: the number of indirection table entries the user
originally provided. When shrinking, the table will not fold below
this floor, preserving user intent.
The user_size is tracked in ctx->indir_user_size for non-default RSS
contexts and in dev->ethtool->rss_indir_user_size for context 0. It
is set when the indirection table is configured via netlink or ioctl,
and cleared to zero on reset-to-default.
Patch 2 uses them in bnxt_set_channels(). Validation runs before
bnxt_close_nic(); actual resize is deferred until after. RSS table
size only changes on P5 chips with older firmware.
Patch 3 adds HW tests in rss_drv.py (devices without dynamic table
sizing are skipped):
resize_periodic - fold/unfold with a non-default [3,2,1,0]
sub-table (user_size=4), verifying exact content preservation
(main + ctx)
resize_below_user_size_reject - periodic sub-table with user_size
between big and small device table sizes; verifies that shrinking
below user_size is rejected even when the table is periodic
(main + ctx)
resize_nonperiodic_reject - non-periodic table blocks channel
reduction, with an extra periodic context to exercise
multi-context validation (main + ctx)
resize_nonperiodic_no_corruption - failed resize leaves table
contents and channel count unchanged (main + ctx)
Running the tests:
# On real hardware
sudo NETIF=eth0 ./rss_drv.py
Changes v4 -> v5:
- Track user-provided indirection table size (user_size) as a resize
floor. Added indir_user_size to ethtool_rxfh_context and
rss_indir_user_size to ethtool_netdev_state. ethtool_rxfh_can_resize()
and ethtool_rxfh_resize() now take a user_size parameter and reject
shrinking below it. (Jakub)
- Propagated user_size out of rss_set_prep_indir() and stored it on
successful set in both netlink and ioctl paths.
- resize_periodic test now sends a 4-entry sub-table (user_size=4)
instead of replicating to full device table size
- Added resize_below_user_size_reject test to verify user_size floor.
- Removed "Open items" section - user_size tracking is now implemented.
Changes v3 -> v4:
- Rebased onto net-next
- Added Reviewed-by: from Michael
- Added missing Cc: to make the pwbots happier
Changes v2 -> v3:
- Changed ethtool_rxfh_can_resize() to return bool instead of int;
true means resize is possible, false means it is not. Inverted
callers accordingly. (Jakub)
- Added Tested-by from Pavan
Changes v1 -> v2:
- Dropped netdevsim support and netdevsim selftest (Jakub)
- Split ethtool_rxfh_contexts_resize_all() into separate validate
(ethtool_rxfh_ctxs_can_resize) and apply (ethtool_rxfh_ctxs_resize)
so drivers can validate before closing the device (Jakub)
- Shortened helper names (Jakub)
- Replaced scoped_guard(mutex) with explicit mutex_lock/unlock
(Jakub)
- Removed defensive zero-size check, bare expressions instead of != 0
comparisons, ! instead of == 0 (Jakub)
- In bnxt, moved bnxt_check_rings() before RSS validation and
deferred actual resize to after bnxt_close_nic() (Jakub, Michael)
- Added comment that RSS table size only changes on P5 chips with
older firmware (Michael)
- Use non-default [3,2,1,0]xN pattern set via netlink to distinguish
correct fold from driver resetting to defaults (Jakub)
- Check exact indirection table pattern, not just set(indir) (Jakub)
- Use ksft_raises() instead of try/except/else (Jakub)
- Removed queue_count=8 from NetDrvEnv (Jakub)
- Added ksft_variants to resize_nonperiodic_reject for ctx coverage
- Added extra periodic context in reject test for multi-context
validation coverage
- Added resize_nonperiodic_no_corruption test
Björn Töpel (3):
ethtool: Add RSS indirection table resize helpers
bnxt_en: Resize RSS contexts on channel count change
selftests: rss_drv: Add RSS indirection table resize tests
.../net/ethernet/broadcom/bnxt/bnxt_ethtool.c | 38 ++-
include/linux/ethtool.h | 11 +
net/ethtool/common.c | 150 +++++++++++
net/ethtool/ioctl.c | 15 +-
net/ethtool/rss.c | 24 +-
.../selftests/drivers/net/hw/rss_drv.py | 233 +++++++++++++++++-
6 files changed, 450 insertions(+), 21 deletions(-)
base-commit: 348baefbb635cbb448e154f38c93657d4cf23936
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2.53.0
