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From:   Jouni Malinen <jouni@codeaurora.org>
To:     Kalle Valo <kvalo@codeaurora.org>
Cc:     ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
        Wen Gong <wgong@codeaurora.org>,
        Jouni Malinen <jouni@codeaurora.org>
Subject: [PATCH 3/3] ath11k: indicate to mac80211 scan complete with aborted flag for ATH11K_SCAN_STARTING state
Date:   Tue, 14 Sep 2021 19:42:26 +0300
Message-Id: <20210914164226.38843-3-jouni@codeaurora.org>
In-Reply-To: <20210914164226.38843-1-jouni@codeaurora.org>
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From: Wen Gong <wgong@codeaurora.org>

Scan failure can not be recovered from when running a loop of the
following steps:
1. run scan: "iw wlan scan".
2. run command: echo assert > /sys/kernel/debug/ath11k/qca6490\ hw2.0/simulate_fw_crash
   immediately after step 1.

result:
scan failed and can not recover even when wlan recovery succeeds:
command failed: Device or resource busy (-16)

reason:
When scan arrives, WMI_START_SCAN_CMDID is sent to the firmware and
function ath11k_mac_op_hw_scan() returns, then simulate_fw_crash arrives
and the scan started event does not arrive, and then it starts to do
recovery of wlan. __ath11k_mac_scan_finish() which is called from
ath11k_core_halt() is one step of recovery, it will not call
ieee80211_scan_completed() by logic currently because the scan state is
ATH11K_SCAN_STARTING. Thus it leads the scan not being completed in
mac80211, and leads all consecutive scans failing with -EBUSY in
nl80211_trigger_scan even after wlan recovery success.

Indicate scan complete with aborted flag to mac80211 for
ATH11K_SCAN_STARTING to allow recovery from scan failed with "Device or
resource busy (-16)" after wlan recovery.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-01720.1-QCAHSPSWPL_V1_V2_SILICONZ_LITE-1

Signed-off-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
---
 drivers/net/wireless/ath/ath11k/mac.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index 97a2c92b7b9b..e015b22b8dbf 100644
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -2985,18 +2985,21 @@ void __ath11k_mac_scan_finish(struct ath11k *ar)
 		break;
 	case ATH11K_SCAN_RUNNING:
 	case ATH11K_SCAN_ABORTING:
+		if (ar->scan.is_roc && ar->scan.roc_notify)
+			ieee80211_remain_on_channel_expired(ar->hw);
+		fallthrough;
+	case ATH11K_SCAN_STARTING:
 		if (!ar->scan.is_roc) {
 			struct cfg80211_scan_info info = {
-				.aborted = (ar->scan.state ==
-					    ATH11K_SCAN_ABORTING),
+				.aborted = ((ar->scan.state ==
+					    ATH11K_SCAN_ABORTING) ||
+					    (ar->scan.state ==
+					    ATH11K_SCAN_STARTING)),
 			};
 
 			ieee80211_scan_completed(ar->hw, &info);
-		} else if (ar->scan.roc_notify) {
-			ieee80211_remain_on_channel_expired(ar->hw);
 		}
-		fallthrough;
-	case ATH11K_SCAN_STARTING:
+
 		ar->scan.state = ATH11K_SCAN_IDLE;
 		ar->scan_channel = NULL;
 		ar->scan.roc_freq = 0;
-- 
2.25.1