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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Goldwyn Rodrigues <rgoldwyn@suse.com>,
        Ping-Ke Shih <pkshih@realtek.com>,
        Johannes Berg <johannes.berg@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 169/239] mac80211: allow non-standard VHT MCS-10/11
Date:   Mon, 24 Jan 2022 19:43:27 +0100
Message-Id: <20220124183948.470185428@linuxfoundation.org>
In-Reply-To: <20220124183943.102762895@linuxfoundation.org>
References: <20220124183943.102762895@linuxfoundation.org>
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From: Ping-Ke Shih <pkshih@realtek.com>

[ Upstream commit 04be6d337d37400ad5b3d5f27ca87645ee5a18a3 ]

Some AP can possibly try non-standard VHT rate and mac80211 warns and drops
packets, and leads low TCP throughput.

    Rate marked as a VHT rate but data is invalid: MCS: 10, NSS: 2
    WARNING: CPU: 1 PID: 7817 at net/mac80211/rx.c:4856 ieee80211_rx_list+0x223/0x2f0 [mac8021

Since commit c27aa56a72b8 ("cfg80211: add VHT rate entries for MCS-10 and MCS-11")
has added, mac80211 adds this support as well.

After this patch, throughput is good and iw can get the bitrate:
    rx bitrate:	975.1 MBit/s VHT-MCS 10 80MHz short GI VHT-NSS 2
or
    rx bitrate:	1083.3 MBit/s VHT-MCS 11 80MHz short GI VHT-NSS 2

Buglink: https://bugzilla.suse.com/show_bug.cgi?id=1192891
Reported-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://lore.kernel.org/r/20220103013623.17052-1-pkshih@realtek.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/mac80211/rx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index e0baa563a4dea..c42cc79895202 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -4620,7 +4620,7 @@ void ieee80211_rx_napi(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,
 				goto drop;
 			break;
 		case RX_ENC_VHT:
-			if (WARN_ONCE(status->rate_idx > 9 ||
+			if (WARN_ONCE(status->rate_idx > 11 ||
 				      !status->nss ||
 				      status->nss > 8,
 				      "Rate marked as a VHT rate but data is invalid: MCS: %d, NSS: %d\n",
-- 
2.34.1