Commit 840110a4 authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by David S. Miller
Browse files

ethtool: Fix preserving of wanted feature bits in netlink interface 



Currently, ethtool-netlink calculates new wanted bits as:
(req_wanted & req_mask) | (old_active & ~req_mask)

It completely discards the old wanted bits, so they are forgotten with
the next ethtool command. Sample steps to reproduce:

1. ethtool -k eth0
   tx-tcp-segmentation: on # TSO is on from the beginning
2. ethtool -K eth0 tx off
   tx-tcp-segmentation: off [not requested]
3. ethtool -k eth0
   tx-tcp-segmentation: off [requested on]
4. ethtool -K eth0 rx off # Some change unrelated to TSO
5. ethtool -k eth0
   tx-tcp-segmentation: off # "Wanted on" is forgotten

This commit fixes it by changing the formula to:
(req_wanted & req_mask) | (old_wanted & ~req_mask),
where old_active was replaced by old_wanted to account for the wanted
bits.

The shortcut condition for the case where nothing was changed now
compares wanted bitmasks, instead of wanted to active.

Fixes: 0980bfcd ("ethtool: set netdev features with FEATURES_SET request")
Signed-off-by: default avatarMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: default avatarMichal Kubecek <mkubecek@suse.cz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4ef1a7cb

net/ethtool/features.c

+7 −4
Original line number Diff line number Diff line
@@ -224,7 +224,9 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info) 
	DECLARE_BITMAP(wanted_diff_mask, NETDEV_FEATURE_COUNT);

	DECLARE_BITMAP(active_diff_mask, NETDEV_FEATURE_COUNT);

	DECLARE_BITMAP(old_active, NETDEV_FEATURE_COUNT);

	DECLARE_BITMAP(old_wanted, NETDEV_FEATURE_COUNT);

	DECLARE_BITMAP(new_active, NETDEV_FEATURE_COUNT);

	DECLARE_BITMAP(new_wanted, NETDEV_FEATURE_COUNT);

	DECLARE_BITMAP(req_wanted, NETDEV_FEATURE_COUNT);

	DECLARE_BITMAP(req_mask, NETDEV_FEATURE_COUNT);

	struct nlattr *tb[ETHTOOL_A_FEATURES_MAX + 1];
@@ -250,6 +252,7 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info) 


	rtnl_lock();

	ethnl_features_to_bitmap(old_active, dev->features);

	ethnl_features_to_bitmap(old_wanted, dev->wanted_features);

	ret = ethnl_parse_bitset(req_wanted, req_mask, NETDEV_FEATURE_COUNT,

				 tb[ETHTOOL_A_FEATURES_WANTED],

				 netdev_features_strings, info->extack);
@@ -261,11 +264,11 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info) 
		goto out_rtnl;

	}



	/* set req_wanted bits not in req_mask from old_active */

	/* set req_wanted bits not in req_mask from old_wanted */

	bitmap_and(req_wanted, req_wanted, req_mask, NETDEV_FEATURE_COUNT);

	bitmap_andnot(new_active, old_active, req_mask, NETDEV_FEATURE_COUNT);

	bitmap_or(req_wanted, new_active, req_wanted, NETDEV_FEATURE_COUNT);

	if (bitmap_equal(req_wanted, old_active, NETDEV_FEATURE_COUNT)) {

	bitmap_andnot(new_wanted, old_wanted, req_mask, NETDEV_FEATURE_COUNT);

	bitmap_or(req_wanted, new_wanted, req_wanted, NETDEV_FEATURE_COUNT);

	if (bitmap_equal(req_wanted, old_wanted, NETDEV_FEATURE_COUNT)) {

		ret = 0;

		goto out_rtnl;

	}