[PATCH wireless v2 1/2] wifi: mt76: mt7915: clear cipher state on key removal for WED offload

[Joshua Klinesmith <joshuaklinesmith@gmail.com>]

When switching from WPA-PSK/SAE to open/no encryption, the
DISABLE_KEY path never resets mvif->mt76.cipher back to zero.
The stale cipher value is sent to the WA firmware via BSS_INFO
updates, causing the firmware to keep the protection bit set on
WED-offloaded packets. The hardware then drops all plaintext
frames, resulting in zero throughput.

Reset mvif->mt76.cipher to zero and notify the firmware via
mt7915_mcu_add_bss_info() when the last group key is removed.

Fixes: 3fd2dbd6a1d3 ("mt76: mt7915: update bss_info with cipher after setting the group key")
Cc: stable@vger.kernel.org
Signed-off-by: Joshua Klinesmith <joshuaklinesmith@gmail.com>
---
 drivers/net/wireless/mediatek/mt76/mt7915/main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/main.c b/drivers/net/wireless/mediatek/mt76/mt7915/main.c
index 90d5e79fbf..6e7442cac4 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/main.c
@@ -414,6 +414,12 @@ static int mt7915_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 	} else {
 		if (idx == *wcid_keyidx)
 			*wcid_keyidx = -1;
+
+		if (!sta && mvif->mt76.cipher) {
+			mvif->mt76.cipher = 0;
+			mt7915_mcu_add_bss_info(phy, vif, true);
+		}
+
 		goto out;
 	}
 
-- 
2.43.0