ath10k: reduce htt tx/rx spinlock overhead

It is inefficient to grab irqsave spinlocks for
skb lists for each queue/dequeue action.

Using rx_ring.lock and tx_lock allows to use less
heavy bh spinlock functions and moving locking
upwards allows to toggle spinlocks less often.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

3 files changed, 23 insertions, 10 deletions

diff --git a/drivers/net/wireless/ath/ath10k/htt_rx.c b/drivers/net/wireless/ath/ath10k/htt_rx.c
index b7150de984e7..8e708dfb63e3 100644
--- a/drivers/net/wireless/ath/ath10k/htt_rx.c
+++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
@@ -274,7 +274,7 @@ static inline struct sk_buff *ath10k_htt_rx_netbuf_pop(struct ath10k_htt *htt)
         int idx;
         struct sk_buff *msdu;
 
-        spin_lock_bh(&htt->rx_ring.lock);
+        lockdep_assert_held(&htt->rx_ring.lock);
 
         if (ath10k_htt_rx_ring_elems(htt) == 0)
                 ath10k_warn("htt rx ring is empty!\n");
@@ -287,7 +287,6 @@ static inline struct sk_buff *ath10k_htt_rx_netbuf_pop(struct ath10k_htt *htt)
         htt->rx_ring.sw_rd_idx.msdu_payld = idx;
         htt->rx_ring.fill_cnt--;
 
-        spin_unlock_bh(&htt->rx_ring.lock);
         return msdu;
 }
 
@@ -311,6 +310,8 @@ static int ath10k_htt_rx_amsdu_pop(struct ath10k_htt *htt,
         struct sk_buff *msdu;
         struct htt_rx_desc *rx_desc;
 
+        lockdep_assert_held(&htt->rx_ring.lock);
+
         if (ath10k_htt_rx_ring_elems(htt) == 0)
                 ath10k_warn("htt rx ring is empty!\n");
 
@@ -918,6 +919,8 @@ static void ath10k_htt_rx_handler(struct ath10k_htt *htt,
         u8 *fw_desc;
         int i, j;
 
+        lockdep_assert_held(&htt->rx_ring.lock);
+
         memset(&info, 0, sizeof(info));
 
         fw_desc_len = __le16_to_cpu(rx->prefix.fw_rx_desc_bytes);
@@ -1055,8 +1058,11 @@ static void ath10k_htt_rx_frag_handler(struct ath10k_htt *htt,
 
         msdu_head = NULL;
         msdu_tail = NULL;
+
+        spin_lock_bh(&htt->rx_ring.lock);
         msdu_chaining = ath10k_htt_rx_amsdu_pop(htt, &fw_desc, &fw_desc_len,
                                                 &msdu_head, &msdu_tail);
+        spin_unlock_bh(&htt->rx_ring.lock);
 
         ath10k_dbg(ATH10K_DBG_HTT_DUMP, "htt rx frag ahead\n");
 
@@ -1158,6 +1164,8 @@ static void ath10k_htt_rx_frm_tx_compl(struct ath10k *ar,
         __le16 msdu_id;
         int i;
 
+        lockdep_assert_held(&htt->tx_lock);
+
         switch (status) {
         case HTT_DATA_TX_STATUS_NO_ACK:
                 tx_done.no_ack = true;
@@ -1204,7 +1212,9 @@ void ath10k_htt_t2h_msg_handler(struct ath10k *ar, struct sk_buff *skb)
                 break;
         }
         case HTT_T2H_MSG_TYPE_RX_IND:
-                skb_queue_tail(&htt->rx_compl_q, skb);
+                spin_lock_bh(&htt->rx_ring.lock);
+                __skb_queue_tail(&htt->rx_compl_q, skb);
+                spin_unlock_bh(&htt->rx_ring.lock);
                 tasklet_schedule(&htt->txrx_compl_task);
                 return;
         case HTT_T2H_MSG_TYPE_PEER_MAP: {
@@ -1298,14 +1308,18 @@ static void ath10k_htt_txrx_compl_task(unsigned long ptr)
         struct htt_resp *resp;
         struct sk_buff *skb;
 
-        while ((skb = skb_dequeue(&htt->tx_compl_q))) {
+        spin_lock_bh(&htt->tx_lock);
+        while ((skb = __skb_dequeue(&htt->tx_compl_q))) {
                 ath10k_htt_rx_frm_tx_compl(htt->ar, skb);
                 dev_kfree_skb_any(skb);
         }
+        spin_unlock_bh(&htt->tx_lock);
 
-        while ((skb = skb_dequeue(&htt->rx_compl_q))) {
+        spin_lock_bh(&htt->rx_ring.lock);
+        while ((skb = __skb_dequeue(&htt->rx_compl_q))) {
                 resp = (struct htt_resp *)skb->data;
                 ath10k_htt_rx_handler(htt, &resp->rx_ind);
                 dev_kfree_skb_any(skb);
         }
+        spin_unlock_bh(&htt->rx_ring.lock);
 }
diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c b/drivers/net/wireless/ath/ath10k/htt_tx.c
index 20b7a446a9f8..7a3e2e40dd5c 100644
--- a/drivers/net/wireless/ath/ath10k/htt_tx.c
+++ b/drivers/net/wireless/ath/ath10k/htt_tx.c
@@ -125,9 +125,7 @@ static void ath10k_htt_tx_cleanup_pending(struct ath10k_htt *htt)
         struct htt_tx_done tx_done = {0};
         int msdu_id;
 
-        /* No locks needed. Called after communication with the device has
-         * been stopped. */
-
+        spin_lock_bh(&htt->tx_lock);
         for (msdu_id = 0; msdu_id < htt->max_num_pending_tx; msdu_id++) {
                 if (!test_bit(msdu_id, htt->used_msdu_ids))
                         continue;
@@ -140,6 +138,7 @@ static void ath10k_htt_tx_cleanup_pending(struct ath10k_htt *htt)
 
                 ath10k_txrx_tx_unref(htt, &tx_done);
         }
+        spin_unlock_bh(&htt->tx_lock);
 }
 
 void ath10k_htt_tx_detach(struct ath10k_htt *htt)
diff --git a/drivers/net/wireless/ath/ath10k/txrx.c b/drivers/net/wireless/ath/ath10k/txrx.c
index 2993ca772c56..0541dd939ce9 100644
--- a/drivers/net/wireless/ath/ath10k/txrx.c
+++ b/drivers/net/wireless/ath/ath10k/txrx.c
@@ -52,6 +52,8 @@ void ath10k_txrx_tx_unref(struct ath10k_htt *htt,
         struct ath10k_skb_cb *skb_cb;
         struct sk_buff *msdu;
 
+        lockdep_assert_held(&htt->tx_lock);
+
         ath10k_dbg(ATH10K_DBG_HTT, "htt tx completion msdu_id %u discard %d no_ack %d\n",
                    tx_done->msdu_id, !!tx_done->discard, !!tx_done->no_ack);
 
@@ -91,13 +93,11 @@ void ath10k_txrx_tx_unref(struct ath10k_htt *htt,
         /* we do not own the msdu anymore */
 
 exit:
-        spin_lock_bh(&htt->tx_lock);
         htt->pending_tx[tx_done->msdu_id] = NULL;
         ath10k_htt_tx_free_msdu_id(htt, tx_done->msdu_id);
         __ath10k_htt_tx_dec_pending(htt);
         if (htt->num_pending_tx == 0)
                 wake_up(&htt->empty_tx_wq);
-        spin_unlock_bh(&htt->tx_lock);
 }
 
 static const u8 rx_legacy_rate_idx[] = {