[v4,0/2] mac80211: Trigger disconnect for STA during target hardware restart

Currently in case of target hardware restart ,we just reconfig and
re-enable the security keys and enable the network queues to start
data traffic back from where it was interrupted.

Many ath10k wifi chipsets have sequence numbers for the data
packets assigned by firmware and the mac sequence number will
restart from zero after target hardware restart leading to mismatch
in the sequence number expected by the remote peer vs the sequence
number of the frame sent by the target firmware.

This mismatch in sequence number will cause out-of-order packets
on the remote peer and all the frames sent by the device are dropped
until we reach the sequence number which was sent before we restarted
the target hardware

In order to fix this, we trigger a disconnect in case of hardware
restart. After this there will be a fresh connection and thereby
avoiding the dropping of frames by remote peer.

The right fix would be to pull the entire data path into the host
which is not feasible or would need lots of complex/inefficient
datapath changes.

---
Changes from v3:
- Added common API to trigger disconnect.

Youghandhar Chintala (2):
  mac80211: Add support to trigger sta disconnect on  hardware restart
  ath10k:trigger sta disconnect on hardware restart

 drivers/net/wireless/ath/ath10k/core.c | 27 ++++++++++++++++++++
 drivers/net/wireless/ath/ath10k/hw.h   |  2 ++
 include/net/mac80211.h                 | 23 +++++++++++++++++
 net/mac80211/ieee80211_i.h             |  3 +++
 net/mac80211/mlme.c                    | 12 +++++++++
 net/mac80211/util.c                    | 34 +++++++++++++++++++++++---
 6 files changed, 98 insertions(+), 3 deletions(-)

On 3/3/2022 3:55 AM, Youghandhar Chintala wrote:

nit: in subject add space after ath10k:

> Currently after the hardware restart triggered from the driver,
> the station interface connection remains intact, since a disconnect
> trigger is not sent to userspace. This can lead to a problem in
> targets where the wifi mac sequence is added by the firmware.
> 
> After the target restart, during subsytem recovery, the target

nit: s/subsytem/subsystem/

> restarts its wifi mac sequence number. Hence AP to which our device
> is connected will receive frames with a  wifi mac sequence number jump
> to the past, thereby resulting in the AP dropping all these frames,
> until the frame arrives with a wifi mac sequence number which AP was
> expecting.
> 
> To avoid such frame drops, its better to trigger a station disconnect
> upon target hardware restart which can be done with API
> ieee80211_reconfig_disconnect exposed to mac80211.
> 
> The other targets are not affected by this change, since the hardware
> params flag is not set.
> 
> Tested-on: WCN3990 hw1.0 SNOC WLAN.HL.3.1-01040-QCAHLSWMTPLZ-1
>             QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00110-QCARMSWP-1
>     	   QCA6174 hw3.2 SDIO WLAN.RMH.4.4.1-00048

<https://wireless.wiki.kernel.org/en/users/drivers/ath10k/submittingpatches#tested-on_tag>

there should be a Tested-on: tag for each line/target

> 
> Signed-off-by: Youghandhar Chintala <youghand@codeaurora.org>
> ---
>   drivers/net/wireless/ath/ath10k/core.c | 25 +++++++++++++++++++++++++
>   drivers/net/wireless/ath/ath10k/hw.h   |  2 ++
>   2 files changed, 27 insertions(+)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> index 9e1f483e1362..2092bfd02cd1 100644
> --- a/drivers/net/wireless/ath/ath10k/core.c
> +++ b/drivers/net/wireless/ath/ath10k/core.c
> @@ -94,6 +94,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = true,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA988X_HW_2_0_VERSION,
> @@ -131,6 +132,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = true,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA9887_HW_1_0_VERSION,
> @@ -169,6 +171,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA6174_HW_3_2_VERSION,
> @@ -202,6 +205,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.bmi_large_size_download = true,
>   		.supports_peer_stats_info = true,
>   		.dynamic_sar_support = true,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA6174_HW_2_1_VERSION,
> @@ -239,6 +243,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA6174_HW_2_1_VERSION,
> @@ -276,6 +281,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA6174_HW_3_0_VERSION,
> @@ -313,6 +319,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA6174_HW_3_2_VERSION,
> @@ -354,6 +361,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.tx_stats_over_pktlog = false,
>   		.supports_peer_stats_info = true,
>   		.dynamic_sar_support = true,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA99X0_HW_2_0_DEV_VERSION,
> @@ -397,6 +405,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA9984_HW_1_0_DEV_VERSION,
> @@ -447,6 +456,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA9888_HW_2_0_DEV_VERSION,
> @@ -494,6 +504,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA9377_HW_1_0_DEV_VERSION,
> @@ -531,6 +542,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA9377_HW_1_1_DEV_VERSION,
> @@ -570,6 +582,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA9377_HW_1_1_DEV_VERSION,
> @@ -600,6 +613,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.uart_pin_workaround = true,
>   		.credit_size_workaround = true,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = QCA4019_HW_1_0_DEV_VERSION,
> @@ -644,6 +658,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = false,
> +		.hw_restart_disconnect = false,
>   	},
>   	{
>   		.id = WCN3990_HW_1_0_DEV_VERSION,
> @@ -674,6 +689,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
>   		.credit_size_workaround = false,
>   		.tx_stats_over_pktlog = false,
>   		.dynamic_sar_support = true,
> +		.hw_restart_disconnect = true,
>   	},
>   };
>   
> @@ -2442,6 +2458,7 @@ EXPORT_SYMBOL(ath10k_core_napi_sync_disable);
>   static void ath10k_core_restart(struct work_struct *work)
>   {
>   	struct ath10k *ar = container_of(work, struct ath10k, restart_work);
> +	struct ath10k_vif *arvif;
>   	int ret;
>   
>   	set_bit(ATH10K_FLAG_CRASH_FLUSH, &ar->dev_flags);
> @@ -2480,6 +2497,14 @@ static void ath10k_core_restart(struct work_struct *work)
>   		ar->state = ATH10K_STATE_RESTARTING;
>   		ath10k_halt(ar);
>   		ath10k_scan_finish(ar);
> +		if (ar->hw_params.hw_restart_disconnect) {
> +			list_for_each_entry(arvif, &ar->arvifs, list) {
> +				if (arvif->is_up &&
> +				    arvif->vdev_type == WMI_VDEV_TYPE_STA)
> +					ieee80211_hw_restart_disconnect(arvif->vif);
> +			}
> +		}
> +
>   		ieee80211_restart_hw(ar->hw);
>   		break;
>   	case ATH10K_STATE_OFF:
> diff --git a/drivers/net/wireless/ath/ath10k/hw.h b/drivers/net/wireless/ath/ath10k/hw.h
> index 5215a6816d71..93acf0dd580a 100644
> --- a/drivers/net/wireless/ath/ath10k/hw.h
> +++ b/drivers/net/wireless/ath/ath10k/hw.h
> @@ -633,6 +633,8 @@ struct ath10k_hw_params {
>   	bool supports_peer_stats_info;
>   
>   	bool dynamic_sar_support;
> +
> +	bool hw_restart_disconnect;
>   };
>   
>   struct htt_resp;