On Tue, 1 Dec 2020 20:53:17 -0800 Vinicius Costa Gomes wrote:
> Frame preemption (described in IEEE 802.3br-2016) defines the concept
> of preemptible and express queues. It allows traffic from express
> queues to "interrupt" traffic from preemptible queues, which are
> "resumed" after the express traffic has finished transmitting.
>
> Frame preemption can only be used when both the local device and the
> link partner support it.
>
> Only parameters for enabling/disabling frame preemption and
> configuring the minimum fragment size are included here. Expressing
> which queues are marked as preemptible is left to mqprio/taprio, as
> having that information there should be easier on the user.
>
> Signed-off-by: Vinicius Costa Gomes <vinicius.go...@intel.com>
> ---
> include/linux/ethtool.h | 19 ++++
> include/uapi/linux/ethtool_netlink.h | 17 +++
> net/ethtool/Makefile | 2 +-
> net/ethtool/netlink.c | 19 ++++
> net/ethtool/netlink.h | 4 +
> net/ethtool/preempt.c | 151 +++++++++++++++++++++++++++
> 6 files changed, 211 insertions(+), 1 deletion(-)
> create mode 100644 net/ethtool/preempt.c
>
> diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
> index e3da25b51ae4..16d6ee29a6ac 100644
> --- a/include/linux/ethtool.h
> +++ b/include/linux/ethtool.h
> @@ -263,6 +263,19 @@ struct ethtool_pause_stats {
> u64 rx_pause_frames;
> };
>
> +/**
> + * struct ethtool_fp - Frame Preemption information
> + *
> + * @enabled: Enable frame preemption.
> + *
The empty line between members seems unnecessary.
> + * @min_frag_size_mult: Minimum size for all non-final fragment size,
> + * expressed in terms of X in '(1 + X)*64 + 4'
Is this way of expressing the min frag size from the standard?
> + */
> +struct ethtool_fp {
> + u8 enabled;
> + u8 min_frag_size_mult;
> +};
> + int (*get_preempt)(struct net_device *,
> + struct ethtool_fp *);
> + int (*set_preempt)(struct net_device *,
> + struct ethtool_fp *);
Since this is a new op we should probably pass extack to the drivers?
> extern const struct nla_policy ethnl_header_policy[ETHTOOL_A_HEADER_FLAGS +
> 1];
> extern const struct nla_policy
> ethnl_header_policy_stats[ETHTOOL_A_HEADER_FLAGS + 1];
> @@ -375,6 +376,8 @@ extern const struct nla_policy
> ethnl_tsinfo_get_policy[ETHTOOL_A_TSINFO_HEADER +
> extern const struct nla_policy
> ethnl_cable_test_act_policy[ETHTOOL_A_CABLE_TEST_HEADER + 1];
> extern const struct nla_policy
> ethnl_cable_test_tdr_act_policy[ETHTOOL_A_CABLE_TEST_TDR_CFG + 1];
> extern const struct nla_policy
> ethnl_tunnel_info_get_policy[ETHTOOL_A_TUNNEL_INFO_HEADER + 1];
> +extern const struct nla_policy
> ethnl_preempt_get_policy[ETHTOOL_A_PREEMPT_MAX + 1];
> +extern const struct nla_policy
> ethnl_preempt_set_policy[ETHTOOL_A_PREEMPT_MAX + 1];
Let's make the size
ETHTOOL_A_PREEMPT_MIN_FRAG_SIZE_MULT + 1
for set, and
ETHTOOL_A_PREEMPT_HEADER + 1
for get, like the other tables
> +const struct nla_policy
> +ethnl_preempt_get_policy[ETHTOOL_A_PREEMPT_MAX + 1] = {
> + [ETHTOOL_A_PREEMPT_UNSPEC] = { .type = NLA_REJECT },
Unnecessary, NLA_REJECT is 0.
> + [ETHTOOL_A_PREEMPT_HEADER] = { .type = NLA_NESTED },
Please specify nested policy
> + [ETHTOOL_A_PREEMPT_ENABLED] = { .type = NLA_REJECT },
> + [ETHTOOL_A_PREEMPT_MIN_FRAG_SIZE_MULT] = { .type = NLA_REJECT },
Unnecessary
> +const struct nla_policy
> +ethnl_preempt_set_policy[ETHTOOL_A_PREEMPT_MAX + 1] = {
> + [ETHTOOL_A_PREEMPT_UNSPEC] = { .type = NLA_REJECT
> },
> + [ETHTOOL_A_PREEMPT_HEADER] = { .type = NLA_NESTED
> },
> + [ETHTOOL_A_PREEMPT_ENABLED] = { .type = NLA_U8 },
Set the right netlink policy to check the value is <= 1.
> + [ETHTOOL_A_PREEMPT_MIN_FRAG_SIZE_MULT] = { .type = NLA_U8 },
> +};
