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helper Message-ID: References: <20260904174134.3789400-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260904174134.3789400-1-kuba@kernel.org> On Fri, Sep 04, 2026 at 10:41:34AM -0700, Jakub Kicinski wrote: > Setting a sysctl or a sysfs attribute for the duration of a test and > putting the old value back has been open coded multiple times. > > We generally avoid creating library helpers but this one is very > common, and the defer is a little tricky as using the same function > for defer as the initial write leads to an infinite loop (not that > I would ever make such mistake!) > > Some of the conversions are not identical, but arguably ctl_file_write() > semantics are more correct. > > Signed-off-by: Jakub Kicinski > --- > CC: shuah@kernel.org > CC: cjubran@nvidia.com > CC: cratiu@nvidia.com > CC: noren@nvidia.com > CC: willemb@google.com > CC: petrm@nvidia.com > CC: linux-kselftest@vger.kernel.org > --- > tools/testing/selftests/drivers/net/gro.py | 17 +++--------- > .../drivers/net/hw/devlink_rate_tc_bw.py | 5 ++-- > tools/testing/selftests/drivers/net/hw/irq.py | 11 ++------ > .../drivers/net/hw/lib/py/__init__.py | 4 +-- > .../selftests/drivers/net/hw/toeplitz.py | 10 +++---- > .../selftests/drivers/net/lib/py/__init__.py | 4 +-- > .../selftests/drivers/net/ring_reconfig.py | 26 ++++--------------- > .../testing/selftests/net/lib/py/__init__.py | 4 +-- > tools/testing/selftests/net/lib/py/utils.py | 22 ++++++++++++++++ > 9 files changed, 44 insertions(+), 59 deletions(-) > > diff --git a/tools/testing/selftests/drivers/net/gro.py b/tools/testing/selftests/drivers/net/gro.py > index 6ab8c97880d1..e0b21703cc3c 100755 > --- a/tools/testing/selftests/drivers/net/gro.py > +++ b/tools/testing/selftests/drivers/net/gro.py > @@ -42,7 +42,7 @@ import re > from lib.py import ksft_run, ksft_exit, ksft_pr > from lib.py import NetDrvEpEnv, KsftFailEx, KsftXfailEx > from lib.py import NetdevFamily, EthtoolFamily > -from lib.py import bkg, cmd, defer, ethtool, ip > +from lib.py import bkg, cmd, ctl_file_write, defer, ethtool, ip > from lib.py import ksft_variants, KsftNamedVariant > > > @@ -79,17 +79,6 @@ GRO_DPORT = 8000 > return getattr(cfg, attr) > > > -def _write_defer_restore(cfg, path, val, defer_undo=False): > - with open(path, "r", encoding="utf-8") as fp: > - orig_val = fp.read().strip() > - if str(val) == orig_val: > - return > - with open(path, "w", encoding="utf-8") as fp: > - fp.write(val) > - if defer_undo: > - defer(_write_defer_restore, cfg, path, orig_val) > - > - > def _set_mtu_restore(dev, mtu, host): > if dev['mtu'] < mtu: > ip(f"link set dev {dev['ifname']} mtu {mtu}", host=host) > @@ -244,8 +233,8 @@ def _run_gro_bin(cfg, test_name, protocol=None, num_flows=None, > flush_path = f"/sys/class/net/{cfg.ifname}/gro_flush_timeout" > irq_path = f"/sys/class/net/{cfg.ifname}/napi_defer_hard_irqs" > > - _write_defer_restore(cfg, flush_path, "200000", defer_undo=True) > - _write_defer_restore(cfg, irq_path, "10", defer_undo=True) > + ctl_file_write(flush_path, "200000") > + ctl_file_write(irq_path, "10") > > _set_ethtool_feat(cfg.ifname, cfg.feat, > {"generic-receive-offload": True, > diff --git a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py > index 4e4faa9275bb..38d712755257 100755 > --- a/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py > +++ b/tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py > @@ -63,7 +63,7 @@ from lib.py import ksft_pr, ksft_run, ksft_exit > from lib.py import KsftSkipEx, KsftFailEx, KsftXfailEx > from lib.py import NetDrvEpEnv, DevlinkFamily > from lib.py import NlError > -from lib.py import cmd, defer, ethtool, ip > +from lib.py import cmd, ctl_file_write, defer, ethtool, ip > from lib.py import Iperf3Runner > > > @@ -113,8 +113,7 @@ from lib.py import Iperf3Runner > except Exception as exc: > raise KsftSkipEx(f"Failed to enable switchdev mode on {cfg.pci}") from exc > try: > - cmd(f"echo 1 > /sys/class/net/{cfg.ifname}/device/sriov_numvfs", shell=True) > - defer(cmd, f"echo 0 > /sys/class/net/{cfg.ifname}/device/sriov_numvfs", shell=True) > + ctl_file_write(f"/sys/class/net/{cfg.ifname}/device/sriov_numvfs", 1) > except Exception as exc: > raise KsftSkipEx(f"Failed to enable SR-IOV on {cfg.ifname}") from exc > > diff --git a/tools/testing/selftests/drivers/net/hw/irq.py b/tools/testing/selftests/drivers/net/hw/irq.py > index 0699d6a8b4e2..3d1c56b51054 100755 > --- a/tools/testing/selftests/drivers/net/hw/irq.py > +++ b/tools/testing/selftests/drivers/net/hw/irq.py > @@ -7,7 +7,7 @@ from lib.py import KsftSkipEx > from lib.py import ksft_disruptive > from lib.py import EthtoolFamily, NetdevFamily > from lib.py import NetDrvEnv > -from lib.py import cmd, ip, defer > +from lib.py import cmd, ctl_file_write, ip > > > def read_affinity(irq) -> str: > @@ -15,12 +15,6 @@ from lib.py import cmd, ip, defer > return fp.read().lstrip("0,").strip() > > > -def write_affinity(irq, what) -> str: > - if what != read_affinity(irq): > - with open(f'/proc/irq/{irq}/smp_affinity', 'w') as fp: > - fp.write(what) > - > - > def check_irqs_reported(cfg) -> None: > """ Check that device reports IRQs for NAPI instances """ > napis = cfg.netnl.napi_get({"ifindex": cfg.ifindex}, dump=True) > @@ -41,8 +35,7 @@ from lib.py import cmd, ip, defer > old = read_affinity(n['irq']) > # pick an affinity that's not the current one > new = "3" if old != "3" else "5" > - write_affinity(n['irq'], new) > - defer(write_affinity, n['irq'], old) > + ctl_file_write(f"/proc/irq/{n['irq']}/smp_affinity", new) This one might miss the ctl_file_write's "old == str(val)" case, where old is still prepended with zeroes (e.g., 0000,0000,0003)? The rest LGTM. Best, Bobby