RE: [PATCH rtw-next v2 7/7] wifi: rtw89: process TX wait skbs for USB via C2H handler

Zong-Zhe Yang
2025-10-03T02:24:26Z

Fedor Pchelkin <pchelkin@ispras.ru> wrote:
>
> TX wait skbs need to be completed when they are done. PCIe part does this inside
> rtw89_pci_tx_status() during RPP processing. Other HCIs use a mechanism based on C2H
> firmware messages.
>
> Store TX wait skbs inside TX report queue so that it'll be possible to identify completed items
> inside C2H handler via private driver data of skb.
>
> Found by Linux Verification Center (linuxtesting.org).
>
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
> ---
>
> v2: store TX wait skbs in tx_rpt_queue (Ping-Ke)
>
> drivers/net/wireless/realtek/rtw89/core.c | 6 ++++--
> drivers/net/wireless/realtek/rtw89/core.h | 15 +++++++++++++++
> drivers/net/wireless/realtek/rtw89/mac.c | 3 ++-
> drivers/net/wireless/realtek/rtw89/mac.h | 15 +++++++++++++--
> drivers/net/wireless/realtek/rtw89/usb.c | 3 ++-
> 5 files changed, 36 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/wireless/realtek/rtw89/core.c
> b/drivers/net/wireless/realtek/rtw89/core.c
> index 214924f8bee0..1457a5fe7320 100644
> --- a/drivers/net/wireless/realtek/rtw89/core.c
> +++ b/drivers/net/wireless/realtek/rtw89/core.c
> @@ -1108,7 +1108,7 @@ rtw89_core_tx_update_desc_info(struct rtw89_dev *rtwdev,
> if (addr_cam->valid && desc_info->mlo)
> upd_wlan_hdr = true;
>
> - if (info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS)
> + if (tx_req->wait || (info->flags &
> + IEEE80211_TX_CTL_REQ_TX_STATUS))
> rtw89_tx_rpt_enable(rtwdev, tx_req);
> }
> is_bmc = (is_broadcast_ether_addr(hdr->addr1) || @@ -1173,7 +1173,8 @@ int
> rtw89_core_tx_kick_off_and_wait(struct rtw89_dev *rtwdev, struct sk_buff *sk
>
> if (time_left == 0) {
> ret = -ETIMEDOUT;
> - list_add_tail(&wait->list, &rtwdev->tx_waits);
> + if (!rtwdev->hci.tx_rpt_enable)
> + list_add_tail(&wait->list, &rtwdev->tx_waits);
> wiphy_delayed_work_queue(rtwdev->hw->wiphy,
> &rtwdev->tx_wait_work,
> RTW89_TX_WAIT_WORK_TIMEOUT);
> } else {
> @@ -1242,6 +1243,7 @@ static int rtw89_core_tx_write_link(struct rtw89_dev *rtwdev,
> tx_req.skb = skb;
> tx_req.vif = vif;
> tx_req.sta = sta;
> + tx_req.wait = wait;
> tx_req.rtwvif_link = rtwvif_link;
> tx_req.rtwsta_link = rtwsta_link;
> tx_req.desc_info.sw_mld = sw_mld; diff --git
> a/drivers/net/wireless/realtek/rtw89/core.h b/drivers/net/wireless/realtek/rtw89/core.h
> index 3940e54353d3..c13465e2730a 100644
> --- a/drivers/net/wireless/realtek/rtw89/core.h
> +++ b/drivers/net/wireless/realtek/rtw89/core.h
> @@ -1201,6 +1201,7 @@ struct rtw89_core_tx_request {
> struct sk_buff *skb;
> struct ieee80211_vif *vif;
> struct ieee80211_sta *sta;
> + struct rtw89_tx_wait_info *wait;
> struct rtw89_vif_link *rtwvif_link;
> struct rtw89_sta_link *rtwsta_link;
> struct rtw89_tx_desc_info desc_info; @@ -7387,6 +7388,20 @@ static inline struct
> sk_buff *rtw89_alloc_skb_for_rx(struct rtw89_dev *rtwdev,
> return dev_alloc_skb(length);
> }
>
> +static inline bool rtw89_core_is_tx_wait(struct rtw89_dev *rtwdev,
> + struct rtw89_tx_skb_data
> +*skb_data) {
> + struct rtw89_tx_wait_info *wait;
> +
> + guard(rcu)();
> +
> + wait = rcu_dereference(skb_data->wait);
> + if (!wait)
> + return false;
> +
> + return true;
> +}
> +

Look like using rcu_access_pointer() is enough for here.

> static inline bool rtw89_core_tx_wait_complete(struct rtw89_dev *rtwdev,
> struct rtw89_tx_skb_data
> *skb_data,
> u8 tx_status) diff --git
> a/drivers/net/wireless/realtek/rtw89/mac.c b/drivers/net/wireless/realtek/rtw89/mac.c
> index 75d9efac452b..3406c8b01eb8 100644
> --- a/drivers/net/wireless/realtek/rtw89/mac.c
> +++ b/drivers/net/wireless/realtek/rtw89/mac.c
> @@ -5484,7 +5484,8 @@ rtw89_mac_c2h_tx_rpt(struct rtw89_dev *rtwdev, struct sk_buff
> *c2h, u32 len)
> continue;
>
> __skb_unlink(cur, &rtwdev->tx_rpt_queue);
> - rtw89_tx_rpt_tx_status(rtwdev, cur, tx_status);
> + if (!rtw89_core_tx_wait_complete(rtwdev, skb_data, tx_status))
> + rtw89_tx_rpt_tx_status(rtwdev, cur, tx_status);
> break;
> }
> spin_unlock_irqrestore(&rtwdev->tx_rpt_queue.lock, flags); diff --git
> a/drivers/net/wireless/realtek/rtw89/mac.h b/drivers/net/wireless/realtek/rtw89/mac.h
> index 1f7d3734d15f..2d647d3b0852 100644
> --- a/drivers/net/wireless/realtek/rtw89/mac.h
> +++ b/drivers/net/wireless/realtek/rtw89/mac.h
> @@ -1647,16 +1647,27 @@ void rtw89_tx_rpt_tx_status(struct rtw89_dev *rtwdev, struct
> sk_buff *skb, u8 tx static inline void rtw89_tx_rpt_queue_purge(struct rtw89_dev *rtwdev)
> {
> + struct rtw89_tx_skb_data *skb_data;
> + struct rtw89_tx_wait_info *wait;
> struct sk_buff_head q;
> struct sk_buff *skb;
> unsigned long flags;
>
> + lockdep_assert_wiphy(rtwdev->hw->wiphy);
> +
> __skb_queue_head_init(&q);
> spin_lock_irqsave(&rtwdev->tx_rpt_queue.lock, flags);
> skb_queue_splice_init(&rtwdev->tx_rpt_queue, &q);
> spin_unlock_irqrestore(&rtwdev->tx_rpt_queue.lock, flags);
>
> - while ((skb = __skb_dequeue(&q)))
> - rtw89_tx_rpt_tx_status(rtwdev, skb, RTW89_TX_MACID_DROP);
> + while ((skb = __skb_dequeue(&q))) {
> + skb_data = RTW89_TX_SKB_CB(skb);
> + wait = wiphy_dereference(rtwdev->hw->wiphy,
> + skb_data->wait);
> +
> + if (wait)
> + rtw89_tx_wait_release(wait);
> + else
> + rtw89_tx_rpt_tx_status(rtwdev, skb, RTW89_TX_MACID_DROP);
> + }
> }
> #endif
> diff --git a/drivers/net/wireless/realtek/rtw89/usb.c
> b/drivers/net/wireless/realtek/rtw89/usb.c
> index f53ab676e9a8..adbadb2783f0 100644
> --- a/drivers/net/wireless/realtek/rtw89/usb.c
> +++ b/drivers/net/wireless/realtek/rtw89/usb.c
> @@ -216,7 +216,8 @@ static void rtw89_usb_write_port_complete(struct urb *urb)
> skb_pull(skb, txdesc_size);
>
> info = IEEE80211_SKB_CB(skb);
> - if (info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS) {
> + if (rtw89_core_is_tx_wait(rtwdev, RTW89_TX_SKB_CB(skb)) ||
> + (info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS)) {
> /* sn is passed to rtw89_mac_c2h_tx_rpt() via driver data */
> skb_queue_tail(&rtwdev->tx_rpt_queue, skb);
> wiphy_delayed_work_queue(rtwdev->hw->wiphy,
> --
> 2.51.0
>