netdev - Re: [PATCH v4 net-next 11/15] net: bridge: switchdev: allow the TX data plane forwarding to be offloaded

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <d81cf0d4-3680-8f87-63ba-d2d843394d5b@gmail.com>
Date:   Sun, 18 Jul 2021 19:43:23 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Vladimir Oltean <vladimir.oltean@....com>, netdev@...r.kernel.org,
        Jakub Kicinski <kuba@...nel.org>,
        "David S. Miller" <davem@...emloft.net>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Ido Schimmel <idosch@...sch.org>,
        Tobias Waldekranz <tobias@...dekranz.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <nikolay@...dia.com>,
        Stephen Hemminger <stephen@...workplumber.org>,
        bridge@...ts.linux-foundation.org,
        Grygorii Strashko <grygorii.strashko@...com>,
        Marek Behun <kabel@...ckhole.sk>,
        DENG Qingfang <dqfext@...il.com>
Subject: Re: [PATCH v4 net-next 11/15] net: bridge: switchdev: allow the TX
 data plane forwarding to be offloaded



On 7/18/2021 2:44 PM, Vladimir Oltean wrote:
> From: Tobias Waldekranz <tobias@...dekranz.com>
> 
> Allow switchdevs to forward frames from the CPU in accordance with the
> bridge configuration in the same way as is done between bridge
> ports. This means that the bridge will only send a single skb towards
> one of the ports under the switchdev's control, and expects the driver
> to deliver the packet to all eligible ports in its domain.
> 
> Primarily this improves the performance of multicast flows with
> multiple subscribers, as it allows the hardware to perform the frame
> replication.
> 
> The basic flow between the driver and the bridge is as follows:
> 
> - When joining a bridge port, the switchdev driver calls
>    switchdev_bridge_port_offload() with tx_fwd_offload = true.
> 
> - The bridge sends offloadable skbs to one of the ports under the
>    switchdev's control using skb->offload_fwd_mark = true.
> 
> - The switchdev driver checks the skb->offload_fwd_mark field and lets
>    its FDB lookup select the destination port mask for this packet.
> 
> v1->v2:
> - convert br_input_skb_cb::fwd_hwdoms to a plain unsigned long
> - introduce a static key "br_switchdev_fwd_offload_used" to minimize the
>    impact of the newly introduced feature on all the setups which don't
>    have hardware that can make use of it
> - introduce a check for nbp->flags & BR_FWD_OFFLOAD to optimize cache
>    line access
> - reorder nbp_switchdev_frame_mark_accel() and br_handle_vlan() in
>    __br_forward()
> - do not strip VLAN on egress if forwarding offload on VLAN-aware bridge
>    is being used
> - propagate errors from .ndo_dfwd_add_station() if not EOPNOTSUPP
> 
> v2->v3:
> - replace the solution based on .ndo_dfwd_add_station with a solution
>    based on switchdev_bridge_port_offload
> - rename BR_FWD_OFFLOAD to BR_TX_FWD_OFFLOAD
> v3->v4: rebase
> 
> Signed-off-by: Tobias Waldekranz <tobias@...dekranz.com>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>

Reviewed-by: Florian Fainelli <f.fainelli@...il.com>
-- 
Florian