[RFC PATCH] ath11k: add ath11k_mac_op_flush_sta to properly flush pending packets

[Sebastian Gottschall]

Am 07.10.2025 um 10:11 schrieb Florian Maurer:

> When a STA is marked as no longer authorized, if the driver doesn't
> implement flush_sta(), mac80211 calls ieee80211_flush_queues() to
> flush hardware queues to avoid sending unencrypted frames.
>
> This has became a problem for ath11k because ieee80211_flush_queues()
> will stop all traffic and call ath11k_flush, which waits until the
> whole HW queue is empty. In a busy environment this will trigger a
> timeout warning and stalls other STAs.
>
> Fix this by implementing flush_sta method using WMI command to flush
> frames of a specific STA.
> Flushed frames will be marked as discard in tx complete indication.
>
> warning print "ath11k c000000.wifi: failed to flush transmit queue 0"
> was observed on various openwrt devices, and is fixed through this patch.
>
> Signed-off-by: Florian Maurer <f.maurer at outlook.de>
> Tested-by: Florian Maurer  <f.maurer at outlook.de>
> Co-authored-by: Benjamin Berg <benjamin at sipsolutions.net>
> Tested-by: Flole <flole at flole.de>
> ---
> We tested this patch and it solved the problem of flushing the transmit
> queues taking too long when the AP is busy.
> We did not confirm if this flush is implemented to guarantee that no
> unencrypted frames are sent out on station removal.
> Could someone with more knowledge about the firmware behavior check
> wether this approach is feasible or if a different approach should be
> taken.
> It is not clear to me if the approach taken in "wifi: ath10k: Flush
> only requested txq in ath10k_flush()" might be better.
> https://lore.kernel.org/linux-wireless/01d859e8e574a1f5d0b916333fe0b5cda859af9b.1732293922.git.repk@triplefau.lt/
>
> Regards
> Florian
>
>   drivers/net/wireless/ath/ath11k/mac.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
>
> diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
> index 106e2530b64e..a94649edd4ed 100644
> --- a/drivers/net/wireless/ath/ath11k/mac.c
> +++ b/drivers/net/wireless/ath/ath11k/mac.c
> @@ -8330,6 +8330,24 @@ static void ath11k_mac_op_flush(struct ieee80211_hw *hw, struct ieee80211_vif *v
>   	ath11k_mac_flush_tx_complete(ar);
>   }
>   
> +static void ath11k_mac_op_flush_sta(struct ieee80211_hw *hw,
> +							struct ieee80211_vif *vif,
> +			    			struct ieee80211_sta *sta)
> +{
> +	struct ath11k_vif *arvif = (void *)vif->drv_priv;
> +	struct ath11k *ar = hw->priv;
> +	struct peer_flush_params params = {
> +		.peer_tid_bitmap = 0xFF,
> +		.vdev_id = arvif->vdev_id,
> +	};
> +	int ret = 0;
> +
> +	ret = ath11k_wmi_send_peer_flush_tids_cmd(ar, sta->addr, &params);
> +	if (ret)
> +		ath11k_warn(ar->ab, "failed to flush sta (sta %pM)\n",
> +			    sta->addr);
> +}
> +
>   static bool
>   ath11k_mac_has_single_legacy_rate(struct ath11k *ar,
>   				  enum nl80211_band band,
> @@ -9920,6 +9938,7 @@ static const struct ieee80211_ops ath11k_ops = {
>   	.set_bitrate_mask		= ath11k_mac_op_set_bitrate_mask,
>   	.get_survey			= ath11k_mac_op_get_survey,
>   	.flush				= ath11k_mac_op_flush,
> +	.flush_sta			= ath11k_mac_op_flush_sta,
>   	.sta_statistics			= ath11k_mac_op_sta_statistics,
>   	CFG80211_TESTMODE_CMD(ath11k_tm_cmd)
>   
why is peer_tid_bitmap 0xff instead of 0xffffffff?