Subject: Re: [PATCH net 4/4] selftests: drv-net: rss_ctx: test RSS contexts persist after ifdown/up

From: Jakub Kicinski <[email-masked]>
Date: Thu, 29 Jan 2026 18:03:20 -0800

On Wed, 28 Jan 2026 22:16:46 -0800 Michael Chan wrote:
> From: Pavan Chebbi <[email-masked]>
> 
> Add tests to verify
> 1. that RSS contexts persist across interface down/up
> 2. that RSS contexts persist across interface down/up along
> with their associated Ntuple fitlers
> 
> Testing on bnxt_en:
> 
>  TAP version 13
>  1..1
>  # timeout set to 0
>  # selftests: drivers/net/hw: rss_ctx.py
>  # TAP version 13
>  # 1..2
>  # ok 1 rss_ctx.test_rss_context_persist_ifupdown
>  # ok 2 rss_ctx.test_rss_context_ntuple_persist_ifupdown
>  # # Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0
>  ok 1 selftests: drivers/net/hw: rss_ctx.py

Thanks for the test. Please make sure that

  ruff check $file

is clean

> diff --git a/tools/testing/selftests/drivers/net/hw/rss_ctx.py b/tools/testing/selftests/drivers/net/hw/rss_ctx.py
> index ed7e405682f0..4e46c5931c7f 100755
> --- a/tools/testing/selftests/drivers/net/hw/rss_ctx.py
> +++ b/tools/testing/selftests/drivers/net/hw/rss_ctx.py
> @@ -809,6 +809,119 @@ def test_rss_default_context_rule(cfg):
>                            'noise' : (0, 1) })
>  
>  

Please put

@ksft_disruptive

decorator before test cases which may disconnect the machine (take the
link down). We won't be able to run them remotely 

> +def test_rss_context_persist_ifupdown(cfg):
> +    """
> +    Check that RSS contexts persist across an interface down/up cycle.
> +    """
> +
> +    require_context_cnt(cfg, 10)

Why 10? I don't think we're gaining any coverage with > 2.

> +    # Create 10 RSS contexts and store their IDs and configurations
> +    ctx_ids = []
> +    ctx_configs_before = {}

appears unused

> +    try:
> +        for i in range(10):
> +            ctx_id = ethtool_create(cfg, "-X", "context new")
> +            ctx_ids.append(ctx_id)
> +            defer(ethtool, f"-X {cfg.ifname} context {ctx_id} delete")
> +    except CmdExitFailure:
> +        raise KsftSkipEx(f"Could only create {len(ctx_ids)} contexts, test requires 10")
> +
> +    # Bring interface down

these comments are pointless and make the whole thing look AI generated

> +    ip(f"link set dev {cfg.ifname} down")
> +
> +    # Bring interface back up
> +    ip(f"link set dev {cfg.ifname} up")
> +
> +    # Wait for interface to be fully up
> +    cfg.wait_hw_stats_settle()

Why?

> +    # Verify all 10 contexts still exist after ifup
> +    missing_contexts = []
> +    persisted_contexts = []
> +
> +    for ctx_id in ctx_ids:
> +        try:
> +            data = get_rss(cfg, context=ctx_id)
> +            _rss_key_check(cfg, data=data, context=ctx_id)
> +            persisted_contexts.append(ctx_id)
> +        except CmdExitFailure:
> +            missing_contexts.append(ctx_id)
> +            ksft_pr(f"Context {ctx_id} is missing after ifup")

You can use netlink to get them all

ctxs = cfg.ethnl.rss_get({}, dump=True)

> +def test_rss_context_ntuple_persist_ifupdown(cfg):
> +    """
> +    Test that RSS contexts and their associated ntuple filters persist across
> +    an interface down/up cycle.
> +    """
> +
> +    require_ntuple(cfg)
> +    require_context_cnt(cfg, 10)
> +
> +    # Create 10 RSS contexts with ntuple filters
> +    ctx_ids = []
> +    ntuple_ids = []
> +    ports = []
> +
> +    try:
> +        for i in range(10):
> +            # Create RSS context
> +            ctx_id = ethtool_create(cfg, "-X", "context new")
> +            ctx_ids.append(ctx_id)
> +            defer(ethtool, f"-X {cfg.ifname} context {ctx_id} delete")
> +
> +            # Create ntuple filter for this context
> +            port = rand_port()
> +            ports.append(port)
> +            flow = f"flow-type tcp{cfg.addr_ipver} dst-ip {cfg.addr} dst-port {port} context {ctx_id}"
> +            ntuple_id = ethtool_create(cfg, "-N", flow)
> +            ntuple_ids.append(ntuple_id)
> +            defer(ethtool, f"-N {cfg.ifname} delete {ntuple_id}")
> +
> +    except CmdExitFailure:
> +        raise KsftSkipEx(f"Could only create {len(ctx_ids)} contexts with ntuple filters, test requires 10")
> +
> +    # Bring interface down
> +    ip(f"link set dev {cfg.ifname} down")
> +
> +    # Bring interface back up
> +    ip(f"link set dev {cfg.ifname} up")
> +
> +    # Wait for interface to be fully up
> +    cfg.wait_hw_stats_settle()
> +
> +    # Verify all contexts and ntuple rules still exist after ifup
> +    missing_contexts = []
> +    persisted_contexts = []
> +    missing_ntuple_rules = []
> +    persisted_ntuple_rules = []
> +    broken_associations = []
> +
> +    for i, ctx_id in enumerate(ctx_ids):
> +        # Check if context persists
> +        try:
> +            data = get_rss(cfg, context=ctx_id)
> +            _rss_key_check(cfg, data=data, context=ctx_id)
> +            persisted_contexts.append(ctx_id)
> +        except CmdExitFailure:
> +            missing_contexts.append(ctx_id)
> +            ksft_pr(f"Context {ctx_id} is missing after ifup")
> +            continue
> +
> +        # Check if ntuple rule persists
> +        ntuple_id = ntuple_ids[i]
> +        try:
> +            _ntuple_rule_check(cfg, ntuple_id, ctx_id)
> +            persisted_ntuple_rules.append(ntuple_id)
> +        except CmdExitFailure:
> +            missing_ntuple_rules.append(ntuple_id)
> +            ksft_pr(f"Ntuple rule {ntuple_id} is missing after ifup")
> +        except Exception as e:
> +            broken_associations.append((ntuple_id, ctx_id))
> +            ksft_pr(f"Ntuple rule {ntuple_id} exists but is not properly associated with context {ctx_id}: {e}")

Not sure why this is a separate test, TBH. You can remove the test
without the ntuple filters. The two cases I would have expected based
on patches is:

tests1:
 - add a couple of contexts
 - add a n-tuple filter to one of the context
 - ifdown/ifup
 - check contexts and filters are there
 - run some traffic to make sure it flows right

tests2:
 - ifdown
 - add a couple of contexts
 - add a n-tuple filter to one of the context
 - ifup
 - check contexts and filters are there
 - run some traffic to make sure it flows right

You can probably have one shared implementation and pass a param to 
it  to tell it whether to "pre-down" the interface.
-- 
pw-bot: cr