ath10k: refactor tx pending management

Tx pending counter logic assumed that the sk_buff
is already known and hence was performed in HTT
functions themselves.

However, for the sake of future wake_tx_queue()
usage the driver must be able to tell whether it
can submit more frames to firmware before it
dequeues frame from ieee80211_txq (and thus long
before HTT Tx functions are called) because once a
frame is dequeued it cannot be requeud back to
mac80211.

This prepares the driver for future changes.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/htt.h

@@ -1753,7 +1753,12 @@ int ath10k_htt_h2t_aggr_cfg_msg(struct ath10k_htt *htt,
 				u8 max_subfrms_amsdu);
 void ath10k_htt_hif_tx_complete(struct ath10k *ar, struct sk_buff *skb);
 
-void __ath10k_htt_tx_dec_pending(struct ath10k_htt *htt, bool limit_mgmt_desc);
+void ath10k_htt_tx_dec_pending(struct ath10k_htt *htt,
+			       bool is_mgmt);
+int ath10k_htt_tx_inc_pending(struct ath10k_htt *htt,
+			      bool is_mgmt,
+			      bool is_presp);
+
 int ath10k_htt_tx_alloc_msdu_id(struct ath10k_htt *htt, struct sk_buff *skb);
 void ath10k_htt_tx_free_msdu_id(struct ath10k_htt *htt, u16 msdu_id);
 int ath10k_htt_mgmt_tx(struct ath10k_htt *htt, struct sk_buff *);

drivers/net/wireless/ath/ath10k/htt_tx.c

@@ -22,9 +22,12 @@
 #include "txrx.h"
 #include "debug.h"
 
-void __ath10k_htt_tx_dec_pending(struct ath10k_htt *htt, bool limit_mgmt_desc)
+void ath10k_htt_tx_dec_pending(struct ath10k_htt *htt,
+			       bool is_mgmt)
 {
-	if (limit_mgmt_desc)
+	lockdep_assert_held(&htt->tx_lock);
+
+	if (is_mgmt)
 		htt->num_pending_mgmt_tx--;
 
 	htt->num_pending_tx--;
@@ -32,43 +35,31 @@ void __ath10k_htt_tx_dec_pending(struct ath10k_htt *htt, bool limit_mgmt_desc)
 		ath10k_mac_tx_unlock(htt->ar, ATH10K_TX_PAUSE_Q_FULL);
 }
 
-static void ath10k_htt_tx_dec_pending(struct ath10k_htt *htt,
-				      bool limit_mgmt_desc)
-{
-	spin_lock_bh(&htt->tx_lock);
-	__ath10k_htt_tx_dec_pending(htt, limit_mgmt_desc);
-	spin_unlock_bh(&htt->tx_lock);
-}
-
-static int ath10k_htt_tx_inc_pending(struct ath10k_htt *htt,
-				     bool limit_mgmt_desc, bool is_probe_resp)
+int ath10k_htt_tx_inc_pending(struct ath10k_htt *htt,
+			      bool is_mgmt,
+			      bool is_presp)
 {
 	struct ath10k *ar = htt->ar;
-	int ret = 0;
 
-	spin_lock_bh(&htt->tx_lock);
+	lockdep_assert_held(&htt->tx_lock);
 
-	if (htt->num_pending_tx >= htt->max_num_pending_tx) {
-		ret = -EBUSY;
-		goto exit;
-	}
+	if (htt->num_pending_tx >= htt->max_num_pending_tx)
+		return -EBUSY;
 
-	if (limit_mgmt_desc) {
-		if (is_probe_resp && (htt->num_pending_mgmt_tx >
-		    ar->hw_params.max_probe_resp_desc_thres)) {
-			ret = -EBUSY;
-			goto exit;
-		}
+	if (is_mgmt &&
+	    is_presp &&
+	    ar->hw_params.max_probe_resp_desc_thres &&
+	    ar->hw_params.max_probe_resp_desc_thres < htt->num_pending_mgmt_tx)
+		return -EBUSY;
+
+	if (is_mgmt)
 		htt->num_pending_mgmt_tx++;
-	}
 
 	htt->num_pending_tx++;
 	if (htt->num_pending_tx == htt->max_num_pending_tx)
 		ath10k_mac_tx_lock(htt->ar, ATH10K_TX_PAUSE_Q_FULL);
 
-exit:
-	spin_unlock_bh(&htt->tx_lock);
-	return ret;
+	return 0;
 }
 
 int ath10k_htt_tx_alloc_msdu_id(struct ath10k_htt *htt, struct sk_buff *skb)
@@ -576,20 +567,6 @@ int ath10k_htt_mgmt_tx(struct ath10k_htt *htt, struct sk_buff *msdu)
 	int msdu_id = -1;
 	int res;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)msdu->data;
-	bool limit_mgmt_desc = false;
-	bool is_probe_resp = false;
-
-	if (ar->hw_params.max_probe_resp_desc_thres) {
-		limit_mgmt_desc = true;
-
-		if (ieee80211_is_probe_resp(hdr->frame_control))
-			is_probe_resp = true;
-	}
-
-	res = ath10k_htt_tx_inc_pending(htt, limit_mgmt_desc, is_probe_resp);
-
-	if (res)
-		goto err;
 
 	len += sizeof(cmd->hdr);
 	len += sizeof(cmd->mgmt_tx);
@@ -598,7 +575,7 @@ int ath10k_htt_mgmt_tx(struct ath10k_htt *htt, struct sk_buff *msdu)
 	res = ath10k_htt_tx_alloc_msdu_id(htt, msdu);
 	spin_unlock_bh(&htt->tx_lock);
 	if (res < 0)
-		goto err_tx_dec;
+		goto err;
 
 	msdu_id = res;
 
@@ -649,8 +626,6 @@ int ath10k_htt_mgmt_tx(struct ath10k_htt *htt, struct sk_buff *msdu)
 	spin_lock_bh(&htt->tx_lock);
 	ath10k_htt_tx_free_msdu_id(htt, msdu_id);
 	spin_unlock_bh(&htt->tx_lock);
-err_tx_dec:
-	ath10k_htt_tx_dec_pending(htt, limit_mgmt_desc);
 err:
 	return res;
 }
@@ -677,26 +652,12 @@ int ath10k_htt_tx(struct ath10k_htt *htt, enum ath10k_hw_txrx_mode txmode,
 	u32 frags_paddr = 0;
 	u32 txbuf_paddr;
 	struct htt_msdu_ext_desc *ext_desc = NULL;
-	bool limit_mgmt_desc = false;
-	bool is_probe_resp = false;
-
-	if (unlikely(ieee80211_is_mgmt(hdr->frame_control)) &&
-	    ar->hw_params.max_probe_resp_desc_thres) {
-		limit_mgmt_desc = true;
-
-		if (ieee80211_is_probe_resp(hdr->frame_control))
-			is_probe_resp = true;
-	}
-
-	res = ath10k_htt_tx_inc_pending(htt, limit_mgmt_desc, is_probe_resp);
-	if (res)
-		goto err;
 
 	spin_lock_bh(&htt->tx_lock);
 	res = ath10k_htt_tx_alloc_msdu_id(htt, msdu);
 	spin_unlock_bh(&htt->tx_lock);
 	if (res < 0)
-		goto err_tx_dec;
+		goto err;
 
 	msdu_id = res;
 
@@ -862,11 +823,7 @@ int ath10k_htt_tx(struct ath10k_htt *htt, enum ath10k_hw_txrx_mode txmode,
 err_unmap_msdu:
 	dma_unmap_single(dev, skb_cb->paddr, msdu->len, DMA_TO_DEVICE);
 err_free_msdu_id:
-	spin_lock_bh(&htt->tx_lock);
 	ath10k_htt_tx_free_msdu_id(htt, msdu_id);
-	spin_unlock_bh(&htt->tx_lock);
-err_tx_dec:
-	ath10k_htt_tx_dec_pending(htt, limit_mgmt_desc);
 err:
 	return res;
 }

drivers/net/wireless/ath/ath10k/mac.c

@@ -3358,13 +3358,11 @@ ath10k_mac_tx_h_get_txpath(struct ath10k *ar,
 
 static int ath10k_mac_tx_submit(struct ath10k *ar,
 				enum ath10k_hw_txrx_mode txmode,
+				enum ath10k_mac_tx_path txpath,
 				struct sk_buff *skb)
 {
 	struct ath10k_htt *htt = &ar->htt;
-	enum ath10k_mac_tx_path txpath;
-	int ret;
-
-	txpath = ath10k_mac_tx_h_get_txpath(ar, skb, txmode);
+	int ret = -EINVAL;
 
 	switch (txpath) {
 	case ATH10K_MAC_TX_HTT:
@@ -3398,6 +3396,7 @@ static int ath10k_mac_tx(struct ath10k *ar,
 			 struct ieee80211_vif *vif,
 			 struct ieee80211_sta *sta,
 			 enum ath10k_hw_txrx_mode txmode,
+			 enum ath10k_mac_tx_path txpath,
 			 struct sk_buff *skb)
 {
 	struct ieee80211_hw *hw = ar->hw;
@@ -3437,7 +3436,7 @@ static int ath10k_mac_tx(struct ath10k *ar,
 		}
 	}
 
-	ret = ath10k_mac_tx_submit(ar, txmode, skb);
+	ret = ath10k_mac_tx_submit(ar, txmode, txpath, skb);
 	if (ret) {
 		ath10k_warn(ar, "failed to submit frame: %d\n", ret);
 		return ret;
@@ -3465,6 +3464,7 @@ void ath10k_offchan_tx_work(struct work_struct *work)
 	struct ath10k_peer *peer;
 	struct ath10k_vif *arvif;
 	enum ath10k_hw_txrx_mode txmode;
+	enum ath10k_mac_tx_path txpath;
 	struct ieee80211_hdr *hdr;
 	struct ieee80211_vif *vif;
 	struct ieee80211_sta *sta;
@@ -3533,8 +3533,9 @@ void ath10k_offchan_tx_work(struct work_struct *work)
 		}
 
 		txmode = ath10k_mac_tx_h_get_txmode(ar, vif, sta, skb);
+		txpath = ath10k_mac_tx_h_get_txpath(ar, skb, txmode);
 
-		ret = ath10k_mac_tx(ar, vif, sta, txmode, skb);
+		ret = ath10k_mac_tx(ar, vif, sta, txmode, txpath, skb);
 		if (ret) {
 			ath10k_warn(ar, "failed to transmit offchannel frame: %d\n",
 				    ret);
@@ -3758,19 +3759,53 @@ static void ath10k_mac_op_tx(struct ieee80211_hw *hw,
 			     struct sk_buff *skb)
 {
 	struct ath10k *ar = hw->priv;
+	struct ath10k_htt *htt = &ar->htt;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	struct ieee80211_vif *vif = info->control.vif;
 	struct ieee80211_sta *sta = control->sta;
+	struct ieee80211_hdr *hdr = (void *)skb->data;
 	enum ath10k_hw_txrx_mode txmode;
+	enum ath10k_mac_tx_path txpath;
+	bool is_htt;
+	bool is_mgmt;
+	bool is_presp;
 	int ret;
 
 	ath10k_mac_tx_h_fill_cb(ar, vif, skb);
 
 	txmode = ath10k_mac_tx_h_get_txmode(ar, vif, sta, skb);
+	txpath = ath10k_mac_tx_h_get_txpath(ar, skb, txmode);
+	is_htt = (txpath == ATH10K_MAC_TX_HTT ||
+		  txpath == ATH10K_MAC_TX_HTT_MGMT);
 
-	ret = ath10k_mac_tx(ar, vif, sta, txmode, skb);
-	if (ret)
+	if (is_htt) {
+		spin_lock_bh(&ar->htt.tx_lock);
+
+		is_mgmt = ieee80211_is_mgmt(hdr->frame_control);
+		is_presp = ieee80211_is_probe_resp(hdr->frame_control);
+
+		ret = ath10k_htt_tx_inc_pending(htt, is_mgmt, is_presp);
+		if (ret) {
+			ath10k_warn(ar, "failed to increase tx pending count: %d, dropping\n",
+				    ret);
+			spin_unlock_bh(&ar->htt.tx_lock);
+			ieee80211_free_txskb(ar->hw, skb);
+			return;
+		}
+
+		spin_unlock_bh(&ar->htt.tx_lock);
+	}
+
+	ret = ath10k_mac_tx(ar, vif, sta, txmode, txpath, skb);
+	if (ret) {
 		ath10k_warn(ar, "failed to transmit frame: %d\n", ret);
+		if (is_htt) {
+			spin_lock_bh(&ar->htt.tx_lock);
+			ath10k_htt_tx_dec_pending(htt, is_mgmt);
+			spin_unlock_bh(&ar->htt.tx_lock);
+		}
+		return;
+	}
 }
 
 /* Must not be called with conf_mutex held as workers can use that also. */

drivers/net/wireless/ath/ath10k/txrx.c

@@ -86,7 +86,7 @@ void ath10k_txrx_tx_unref(struct ath10k_htt *htt,
 		limit_mgmt_desc = true;
 
 	ath10k_htt_tx_free_msdu_id(htt, tx_done->msdu_id);
-	__ath10k_htt_tx_dec_pending(htt, limit_mgmt_desc);
+	ath10k_htt_tx_dec_pending(htt, limit_mgmt_desc);
 	if (htt->num_pending_tx == 0)
 		wake_up(&htt->empty_tx_wq);
 	spin_unlock_bh(&htt->tx_lock);