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Subject: Re: [PATCH 4.20 018/352] ath9k: dynack: use authentication messages
 for late ack
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     stable@vger.kernel.org,
        Lorenzo Bianconi <lorenzo.bianconi@redhat.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        Sasha Levin <sashal@kernel.org>
References: <20190211141846.543045703@linuxfoundation.org>
 <20190211141847.541071852@linuxfoundation.org>
From:   Koen Vandeputte <koen.vandeputte@ncentric.com>
Message-ID: <e3740a06-8735-eed3-b427-e924f3e185ae@ncentric.com>
Date:   Mon, 11 Feb 2019 16:48:30 +0100
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On 11.02.19 15:14, Greg Kroah-Hartman wrote:
> 4.20-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> [ Upstream commit 3831a2a0010c72e3956020cbf1057a1701a2e469 ]
>
> In order to properly support dynack in ad-hoc mode running
> wpa_supplicant, take into account authentication frames for
> 'late ack' detection. This patch has been tested on devices
> mounted on offshore high-voltage stations connected through
> ~24Km link
>
> Reported-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
> Tested-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>   drivers/net/wireless/ath/ath9k/dynack.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/ath9k/dynack.c b/drivers/net/wireless/ath/ath9k/dynack.c
> index 7334c9b09e82..cc0dc966c512 100644
> --- a/drivers/net/wireless/ath/ath9k/dynack.c
> +++ b/drivers/net/wireless/ath/ath9k/dynack.c
> @@ -187,7 +187,8 @@ void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
>   	/* late ACK */
>   	if (ts->ts_status & ATH9K_TXERR_XRETRY) {
>   		if (ieee80211_is_assoc_req(hdr->frame_control) ||
> -		    ieee80211_is_assoc_resp(hdr->frame_control)) {
> +		    ieee80211_is_assoc_resp(hdr->frame_control) ||
> +		    ieee80211_is_auth(hdr->frame_control)) {
>   			ath_dbg(common, DYNACK, "late ack\n");
>   			ath9k_hw_setslottime(ah, (LATEACK_TO - 3) / 2);
>   			ath9k_hw_set_ack_timeout(ah, LATEACK_TO);

Dear Greg,

No idea if this is the proper location to report this or if I should 
inform stable@vger.. , but:

This backport alone is useless without backporting following 2 commits 
below also, unless the 2 wifi devices using dynack start off at very 
close distance.

Their commits messages indicate them as improvements, but they should be 
considered as fixes.


https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.0-rc6&id=0c60c490830a1a756c80f8de8d33d9c6359d4a36

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.0-rc6&id=9d3d65a91f027b8a9af5e63752d9b78cb10eb92d


It's safe to add them to all stables involved (4.20, 4.19, 4.14, 4.9)

Thanks,

Koen