On Mon, Aug 17, 2020 at 04:34:05PM +0300, Maxim Mikityanskiy wrote:
> 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: 0980bfcd6954 ("ethtool: set netdev features with FEATURES_SET request")
> Signed-off-by: Maxim Mikityanskiy <maxi...@mellanox.com>
> ---
Reviewed-by: Michal Kubecek <mkube...@suse.cz>
> net/ethtool/features.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/net/ethtool/features.c b/net/ethtool/features.c
> index 4e632dc987d8..ec196f0fddc9 100644
> --- a/net/ethtool/features.c
> +++ b/net/ethtool/features.c
> @@ -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;
> }
> --
> 2.25.1
>
signature.asc
Description: PGP signature
