[PATCH ath-next v2 5/5] wifi: ath11k: hold back WMI commands while the firmware restarts

[Julius Bairaktaris <julius@bairaktaris.de>]

ath11k_core_restart() brings the firmware up outside mac80211's restart,
so cfg80211 operations keep sending WMI commands while the HTC services
reconnect and before the firmware reports ready. These commands crash
the restarting firmware again, and recovery then fails on the unified
ready timeout:

  ath11k c000000.wifi: failed to receive wmi unified ready event: -110
  ath11k c000000.wifi: failed to reconfigure driver on crash recovery

With iw setting the RTS threshold in a loop from the moment the firmware
stops, the firmware crashed 15, 15 and 11 times on three triggers
before recovery succeeded. With this patch it crashed once per trigger
(5 of 5).

Return -ESHUTDOWN for commands from outside the restart worker while
ATH11K_FLAG_RECOVERY is set. mac80211 replays the configuration when the
driver restarts the hardware.

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.9.0.1-02146-QCAHKSWPL_SILICONZ-1

Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Julius Bairaktaris <julius@bairaktaris.de>
---
 drivers/net/wireless/ath/ath11k/wmi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/wireless/ath/ath11k/wmi.c b/drivers/net/wireless/ath/ath11k/wmi.c
index 3d5b6605eace8..5c27e7057e6ad 100644
--- a/drivers/net/wireless/ath/ath11k/wmi.c
+++ b/drivers/net/wireless/ath/ath11k/wmi.c
@@ -312,6 +312,10 @@ int ath11k_wmi_cmd_send(struct ath11k_pdev_wmi *wmi, struct sk_buff *skb,
 
 	might_sleep();
 
+	if (test_bit(ATH11K_FLAG_RECOVERY, &ab->dev_flags) &&
+	    current_work() != &ab->restart_work)
+		return -ESHUTDOWN;
+
 	if (ab->hw_params.credit_flow) {
 		wait_event_timeout(wmi_ab->tx_credits_wq, ({
 			ret = ath11k_wmi_cmd_send_nowait(wmi, skb, cmd_id);
-- 
2.53.0