Commit 2677010e7793 ("Add support to set NAPI threaded for individual NAPI") added support to enable/disable threaded napi using netlink. This also extended the napi config save/restore functionality to set the napi threaded state. This breaks netdev reset for drivers that use napi threaded at device level and also use napi config save/restore on napi_disable/napi_enable. Basically on netdev with napi threaded enabled at device level, a napi_enable call will get stuck trying to stop the napi kthread. This is because the napi->config->threaded is set to disabled when threaded is enabled at device level. The issue can be reproduced on virtio-net device using qemu. To reproduce the issue run following, echo 1 > /sys/class/net/threaded ethtool -L eth0 combined 1 Update the threaded state in napi config in netif_set_threaded and add a new test that verifies this scenario. Tested on qemu with virtio-net: NETIF=eth0 ./tools/testing/selftests/drivers/net/napi_threaded.py TAP version 13 1..2 ok 1 napi_threaded.change_num_queues ok 2 napi_threaded.enable_dev_threaded_disable_napi_threaded # Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0 Fixes: 2677010e7793 ("Add support to set NAPI threaded for individual NAPI") Signed-off-by: Samiullah Khawaja --- v2: - Setting napi threaded state in napi config when enabled at device level instead of skipping napi_set_threaded in napi_restore_config. - Added a new test in tools/testing/selftest/drivers/net. --- net/core/dev.c | 3 + .../selftests/drivers/net/napi_threaded.py | 108 ++++++++++++++++++ 2 files changed, 111 insertions(+) create mode 100755 tools/testing/selftests/drivers/net/napi_threaded.py diff --git a/net/core/dev.c b/net/core/dev.c index 1c6e755841ce..1abba4fc1eec 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7023,6 +7023,9 @@ int netif_set_threaded(struct net_device *dev, * This should not cause hiccups/stalls to the live traffic. */ list_for_each_entry(napi, &dev->napi_list, dev_list) { + if (napi->config) + napi->config->threaded = threaded; + if (!threaded && napi->thread) napi_stop_kthread(napi); else diff --git a/tools/testing/selftests/drivers/net/napi_threaded.py b/tools/testing/selftests/drivers/net/napi_threaded.py new file mode 100755 index 000000000000..f2168864568e --- /dev/null +++ b/tools/testing/selftests/drivers/net/napi_threaded.py @@ -0,0 +1,108 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 + +""" +Test napi threaded states. +""" + +from lib.py import ksft_run, ksft_exit +from lib.py import ksft_eq, ksft_ne +from lib.py import NetDrvEnv, NetdevFamily +from lib.py import cmd, defer, ip + + +def _assert_napi_threaded_enabled(nl, napi_id) -> None: + napi = nl.napi_get({'id': napi_id}) + ksft_eq(napi['threaded'], 'enabled') + ksft_ne(napi.get('pid'), None) + + +def _assert_napi_threaded_disabled(nl, napi_id) -> None: + napi = nl.napi_get({'id': napi_id}) + ksft_eq(napi['threaded'], 'disabled') + ksft_eq(napi.get('pid'), None) + + +def _set_threaded_state(cfg, threaded) -> None: + cmd(f"echo {threaded} > /sys/class/net/{cfg.ifname}/threaded") + + +def enable_dev_threaded_disable_napi_threaded(cfg, nl) -> None: + """ + Test that when napi threaded is enabled at device level and + then disabled at napi level for one napi, the threaded state + of all napis is preserved after a change in number of queues. + """ + + ip(f"link set dev {cfg.ifname} up") + + napis = nl.napi_get({'ifindex': cfg.ifindex}, dump=True) + ksft_eq(len(napis), 2) + + napi0_id = napis[0]['id'] + napi1_id = napis[1]['id'] + + threaded = cmd(f"cat /sys/class/net/{cfg.ifname}/threaded").stdout + defer(_set_threaded_state, cfg, threaded) + + # set threaded + _set_threaded_state(cfg, 1) + + # check napi threaded is set for both napis + _assert_napi_threaded_enabled(nl, napi0_id) + _assert_napi_threaded_enabled(nl, napi1_id) + + # disable threaded for napi1 + nl.napi_set({'id': napi1_id, 'threaded': 'disabled'}) + + cmd(f"ethtool -L {cfg.ifname} combined 1") + cmd(f"ethtool -L {cfg.ifname} combined 2") + _assert_napi_threaded_enabled(nl, napi0_id) + _assert_napi_threaded_disabled(nl, napi1_id) + + +def change_num_queues(cfg, nl) -> None: + """ + Test that when napi threaded is enabled at device level, + the napi threaded state is preserved after a change in + number of queues. + """ + + ip(f"link set dev {cfg.ifname} up") + + napis = nl.napi_get({'ifindex': cfg.ifindex}, dump=True) + ksft_eq(len(napis), 2) + + napi0_id = napis[0]['id'] + napi1_id = napis[1]['id'] + + threaded = cmd(f"cat /sys/class/net/{cfg.ifname}/threaded").stdout + defer(_set_threaded_state, cfg, threaded) + + # set threaded + _set_threaded_state(cfg, 1) + + # check napi threaded is set for both napis + _assert_napi_threaded_enabled(nl, napi0_id) + _assert_napi_threaded_enabled(nl, napi1_id) + + cmd(f"ethtool -L {cfg.ifname} combined 1") + cmd(f"ethtool -L {cfg.ifname} combined 2") + + # check napi threaded is set for both napis + _assert_napi_threaded_enabled(nl, napi0_id) + _assert_napi_threaded_enabled(nl, napi1_id) + + +def main() -> None: + """ Ksft boiler plate main """ + + with NetDrvEnv(__file__, queue_count=2) as cfg: + ksft_run([change_num_queues, + enable_dev_threaded_disable_napi_threaded], + args=(cfg, NetdevFamily())) + ksft_exit() + + +if __name__ == "__main__": + main() base-commit: fa582ca7e187a15e772e6a72fe035f649b387a60 -- 2.50.1.552.g942d659e1b-goog