When hds-thresh is configured, ethnl_set_rings() is called, and it calls
ethtool_ringparam_get_cfg() to get ringparameters from .get_ringparam()
callback and dev->cfg.
Both hds_config and hds_thresh values should be set from dev->cfg, not
from .get_ringparam().
But ethtool_ringparam_get_cfg() sets only hds_config from dev->cfg.
So, ethtool_ringparam_get_cfg() returns always a hds_thresh as 0.
If an input value of hds-thresh is 0, a hds_thresh value from
ethtool_ringparam_get_cfg() are same. So ethnl_set_rings() does
nothing and returns immediately.
It causes a bug that setting a hds-thresh value to 0 is not working.
Reproducer:
modprobe netdevsim
echo 1 > /sys/bus/netdevsim/new_device
ethtool -G eth0 hds-thresh 100
ethtool -G eth0 hds-thresh 0
ethtool -g eth0
#hds-thresh value should be 0, but it shows 100.
The tools/testing/selftests/drivers/net/hds.py can test it too with
applying a following patch for hds.py.
Fixes: 928459bbda19 ("net: ethtool: populate the default HDS params in the
core")
Signed-off-by: Taehee Yoo <[email protected]>
---
The ethtool command doesn't support hds-thresh option yet.
So, RFC[1] patch is needed to be applied.
v2:
- No changes.
net/ethtool/common.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index 0cb6da1f692a..49bea6b45bd5 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -830,6 +830,7 @@ void ethtool_ringparam_get_cfg(struct net_device *dev,
/* Driver gives us current state, we want to return current config */
kparam->tcp_data_split = dev->cfg->hds_config;
+ kparam->hds_thresh = dev->cfg->hds_thresh;
}
static void ethtool_init_tsinfo(struct kernel_ethtool_ts_info *info)
--
2.34.1
