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From:   Kalle Valo <kvalo@kernel.org>
To:     Sriram R <quic_srirrama@quicinc.com>
Cc:     <johannes@sipsolutions.net>, <nbd@nbd.name>,
        <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH v2] mac80211: Mesh Fast xmit support
References: <20220801070418.5420-1-quic_srirrama@quicinc.com>
Date:   Mon, 01 Aug 2022 12:54:00 +0300
In-Reply-To: <20220801070418.5420-1-quic_srirrama@quicinc.com> (Sriram R.'s
        message of "Mon, 1 Aug 2022 12:34:18 +0530")
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Sriram R <quic_srirrama@quicinc.com> writes:

> Currently Fast xmit is supported in AP, STA and other device types where
> the destination doesn't change for the lifetime of its association by
> caching the static parts of the header that can be reused directly for
> every Tx such as addresses and updates only mutable header fields such as
> PN. This technique is not directly applicable for a Mesh device type
> due to the dynamic nature of the topology and protocol. The header is
> built based on the destination mesh device which is proxying a certain
> external device and based on the Mesh destination the next hop changes.
> And the RA/A1 which is the next hop for reaching the destination can
> vary during runtime as per the best route based on airtime.  To
> accommodate these changes and to come up with a solution to avoid
> overhead during header generation, the headers comprising the MAC, Mesh
> and LLC part are cached whenever data for a certain external destination
> is sent. This cached header is reused every time a data is sent to that
> external destination.
>
> To ensure the changes in network are reflected in these cached headers,
> the Mesh Proxy path table and Mesh path table changes are monitored
> and corresponding headers are updated or flushed as applicable so that
> the header used for a frame towards a certain destination is valid.
>
> Old headers are flushed by the mesh housekeeping timers and based on the
> cache size.
>
> Only 6addr frame headers are cached currently.
>
> Tested with ath11k driver.
>
> Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
> ---
> v2: Moved to static header cache size of 512 entries
>     Rearranged entry struct to avoid padding
>     Used GFP_ATOMIC while entry allocation in tx path
>     Compile tested from previous version - only above trivial changes
>
>  net/mac80211/ieee80211_i.h  |  20 ++
>  net/mac80211/mesh.c         |   2 +
>  net/mac80211/mesh.h         |  46 +++++
>  net/mac80211/mesh_hwmp.c    |   8 +-
>  net/mac80211/mesh_pathtbl.c | 396 ++++++++++++++++++++++++++++++++++++
>  net/mac80211/rx.c           |   9 +-
>  net/mac80211/tx.c           |  89 ++++++++
>  7 files changed, 566 insertions(+), 4 deletions(-)

The title should be:

wifi: mac80211: Mesh Fast xmit support

But I suspect Johannes can fix that so no need resend because of this.

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