ath10k: drop probe responses when too many are queued

In a noisy environment, when multiple interfaces are created,
the management tx descriptors are fully occupied by the probe
responses from all the interfaces. This prevents a new station
from a successful association.

Fix this by limiting the probe responses when the specified
threshold limit is reached.

Signed-off-by: Vivek Natarajan <nataraja@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

1 files changed, 44 insertions, 8 deletions

diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c b/drivers/net/wireless/ath/ath10k/htt_tx.c
index 43aa5e2d1b87..ea53c2151122 100644
--- a/drivers/net/wireless/ath/ath10k/htt_tx.c
+++ b/drivers/net/wireless/ath/ath10k/htt_tx.c
@@ -22,22 +22,28 @@
 #include "txrx.h"
 #include "debug.h"
 
-void __ath10k_htt_tx_dec_pending(struct ath10k_htt *htt)
+void __ath10k_htt_tx_dec_pending(struct ath10k_htt *htt, bool limit_mgmt_desc)
 {
+	if (limit_mgmt_desc)
+		htt->num_pending_mgmt_tx--;
+
 	htt->num_pending_tx--;
 	if (htt->num_pending_tx == htt->max_num_pending_tx - 1)
 		ath10k_mac_tx_unlock(htt->ar, ATH10K_TX_PAUSE_Q_FULL);
 }
 
-static void ath10k_htt_tx_dec_pending(struct ath10k_htt *htt)
+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);
+	__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)
+static int ath10k_htt_tx_inc_pending(struct ath10k_htt *htt,
+				     bool limit_mgmt_desc, bool is_probe_resp)
 {
+	struct ath10k *ar = htt->ar;
 	int ret = 0;
 
 	spin_lock_bh(&htt->tx_lock);
@@ -47,6 +53,15 @@ static int ath10k_htt_tx_inc_pending(struct ath10k_htt *htt)
 		goto exit;
 	}
 
+	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;
+		}
+		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);
@@ -417,8 +432,19 @@ int ath10k_htt_mgmt_tx(struct ath10k_htt *htt, struct sk_buff *msdu)
 	int len = 0;
 	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);
 
-	res = ath10k_htt_tx_inc_pending(htt);
 	if (res)
 		goto err;
 
@@ -476,7 +502,7 @@ err_free_msdu_id:
 	ath10k_htt_tx_free_msdu_id(htt, msdu_id);
 	spin_unlock_bh(&htt->tx_lock);
 err_tx_dec:
-	ath10k_htt_tx_dec_pending(htt);
+	ath10k_htt_tx_dec_pending(htt, limit_mgmt_desc);
 err:
 	return res;
 }
@@ -498,8 +524,18 @@ int ath10k_htt_tx(struct ath10k_htt *htt, struct sk_buff *msdu)
 	dma_addr_t paddr = 0;
 	u32 frags_paddr = 0;
 	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);
+	res = ath10k_htt_tx_inc_pending(htt, limit_mgmt_desc, is_probe_resp);
 	if (res)
 		goto err;
 
@@ -678,7 +714,7 @@ err_free_msdu_id:
 	ath10k_htt_tx_free_msdu_id(htt, msdu_id);
 	spin_unlock_bh(&htt->tx_lock);
 err_tx_dec:
-	ath10k_htt_tx_dec_pending(htt);
+	ath10k_htt_tx_dec_pending(htt, limit_mgmt_desc);
 err:
 	return res;
 }