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

[Jeff Johnson]

On 10/7/2025 1:11 AM, Florian Maurer wrote:
> 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>

Your SOB should be the last tag in the list of tags since you need to sign off
on the other tags you have added

> Tested-by: Florian Maurer  <f.maurer at outlook.de>
> Co-authored-by: Benjamin Berg <benjamin at sipsolutions.net>

This is not an upstream kernel tag. Perhaps you meant:
Co-developed-by:

https://www.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by

Note that a Signed-off-by: tag is needed for all contributors

> 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,

CHECK:PARENTHESIS_ALIGNMENT: Alignment should match open parenthesis

> +			    			struct ieee80211_sta *sta)

ERROR:CODE_INDENT: code indent should use tabs where possible
WARNING:SPACE_BEFORE_TAB: please, no space before tabs

> +{
> +	struct ath11k_vif *arvif = (void *)vif->drv_priv;

use = ath11k_vif_to_arvif(vif)

> +	struct ath11k *ar = hw->priv;
> +	struct peer_flush_params params = {
> +		.peer_tid_bitmap = 0xFF,
> +		.vdev_id = arvif->vdev_id,
> +	};
> +	int ret = 0;

unnecessary initializer that is always overwritten

> +
> +	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",

avoid unnecessary parenthesis, and include the error code, i.e.:
"failed to flush sta %pM: %d", sta->addr, ret

> +			    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)
>  
These are just cosmetic comments. I've asked both the infrastructure and the
mobile teams to validate this proposal for technical correctness.

/jeff