[PATCH ath-next v3 3/4] wifi: ath12k: Fix memory leak during extended skb allocation

[P Praneesh]

In ath12k_dp_tx(), memory allocated for extended skb is not freed
properly, causing a memory leak even when the host receives tx
completion for those skbs. Fix this issue by storing skb_ext_desc
in the host tx descriptor and using this skb_ext_desc field during
completion or during ath12k_dp_cc_cleanup().

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.4.1-00199-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: P Praneesh <praneesh.p at oss.qualcomm.com>
---
 drivers/net/wireless/ath/ath12k/dp.c    | 10 +++++++++-
 drivers/net/wireless/ath/ath12k/dp.h    |  2 ++
 drivers/net/wireless/ath/ath12k/dp_tx.c | 15 ++++++++++++---
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/dp.c b/drivers/net/wireless/ath/ath12k/dp.c
index b8e63f489e7d..ad873013e46c 100644
--- a/drivers/net/wireless/ath/ath12k/dp.c
+++ b/drivers/net/wireless/ath/ath12k/dp.c
@@ -1206,11 +1206,19 @@ static void ath12k_dp_cc_cleanup(struct ath12k_base *ab)
 			if (!skb)
 				continue;
 
+			skb_cb = ATH12K_SKB_CB(skb);
+			if (skb_cb->paddr_ext_desc) {
+				dma_unmap_single(ab->dev,
+						 skb_cb->paddr_ext_desc,
+						 tx_desc_info->skb_ext_desc->len,
+						 DMA_TO_DEVICE);
+				dev_kfree_skb_any(tx_desc_info->skb_ext_desc);
+			}
+
 			/* if we are unregistering, hw would've been destroyed and
 			 * ar is no longer valid.
 			 */
 			if (!(test_bit(ATH12K_FLAG_UNREGISTERING, &ab->dev_flags))) {
-				skb_cb = ATH12K_SKB_CB(skb);
 				ar = skb_cb->ar;
 
 				if (atomic_dec_and_test(&ar->dp.num_tx_pending))
diff --git a/drivers/net/wireless/ath/ath12k/dp.h b/drivers/net/wireless/ath/ath12k/dp.h
index 241da2a3bd34..706d766d8c81 100644
--- a/drivers/net/wireless/ath/ath12k/dp.h
+++ b/drivers/net/wireless/ath/ath12k/dp.h
@@ -296,6 +296,7 @@ struct ath12k_rx_desc_info {
 struct ath12k_tx_desc_info {
 	struct list_head list;
 	struct sk_buff *skb;
+	struct sk_buff *skb_ext_desc;
 	u32 desc_id; /* Cookie */
 	u8 mac_id;
 	u8 pool_id;
@@ -303,6 +304,7 @@ struct ath12k_tx_desc_info {
 
 struct ath12k_tx_desc_params {
 	struct sk_buff *skb;
+	struct sk_buff *skb_ext_desc;
 	u8 mac_id;
 };
 
diff --git a/drivers/net/wireless/ath/ath12k/dp_tx.c b/drivers/net/wireless/ath/ath12k/dp_tx.c
index a272d5b8a51c..9bcd20712888 100644
--- a/drivers/net/wireless/ath/ath12k/dp_tx.c
+++ b/drivers/net/wireless/ath/ath12k/dp_tx.c
@@ -84,6 +84,7 @@ static void ath12k_dp_tx_release_txbuf(struct ath12k_dp *dp,
 				       u8 pool_id)
 {
 	spin_lock_bh(&dp->tx_desc_lock[pool_id]);
+	tx_desc->skb_ext_desc = NULL;
 	list_move_tail(&tx_desc->list, &dp->tx_desc_free_list[pool_id]);
 	spin_unlock_bh(&dp->tx_desc_lock[pool_id]);
 }
@@ -431,6 +432,7 @@ int ath12k_dp_tx(struct ath12k *ar, struct ath12k_link_vif *arvif,
 		ti.type = HAL_TCL_DESC_TYPE_EXT_DESC;
 
 		skb_cb->paddr_ext_desc = ti.paddr;
+		tx_desc->skb_ext_desc = skb_ext_desc;
 	}
 
 	hal_ring_id = tx_ring->tcl_data_ring.ring_id;
@@ -525,9 +527,11 @@ static void ath12k_dp_tx_free_txbuf(struct ath12k_base *ab,
 	ar = ab->pdevs[pdev_id].ar;
 
 	dma_unmap_single(ab->dev, skb_cb->paddr, msdu->len, DMA_TO_DEVICE);
-	if (skb_cb->paddr_ext_desc)
+	if (skb_cb->paddr_ext_desc) {
 		dma_unmap_single(ab->dev, skb_cb->paddr_ext_desc,
 				 sizeof(struct hal_tx_msdu_ext_desc), DMA_TO_DEVICE);
+		dev_kfree_skb_any(desc_params->skb_ext_desc);
+	}
 
 	ieee80211_free_txskb(ar->ah->hw, msdu);
 
@@ -558,9 +562,11 @@ ath12k_dp_tx_htt_tx_complete_buf(struct ath12k_base *ab,
 		wake_up(&ar->dp.tx_empty_waitq);
 
 	dma_unmap_single(ab->dev, skb_cb->paddr, msdu->len, DMA_TO_DEVICE);
-	if (skb_cb->paddr_ext_desc)
+	if (skb_cb->paddr_ext_desc) {
 		dma_unmap_single(ab->dev, skb_cb->paddr_ext_desc,
 				 sizeof(struct hal_tx_msdu_ext_desc), DMA_TO_DEVICE);
+		dev_kfree_skb_any(desc_params->skb_ext_desc);
+	}
 
 	vif = skb_cb->vif;
 	if (vif) {
@@ -773,9 +779,11 @@ static void ath12k_dp_tx_complete_msdu(struct ath12k *ar,
 	skb_cb = ATH12K_SKB_CB(msdu);
 
 	dma_unmap_single(ab->dev, skb_cb->paddr, msdu->len, DMA_TO_DEVICE);
-	if (skb_cb->paddr_ext_desc)
+	if (skb_cb->paddr_ext_desc) {
 		dma_unmap_single(ab->dev, skb_cb->paddr_ext_desc,
 				 sizeof(struct hal_tx_msdu_ext_desc), DMA_TO_DEVICE);
+		dev_kfree_skb_any(desc_params->skb_ext_desc);
+	}
 
 	rcu_read_lock();
 
@@ -953,6 +961,7 @@ void ath12k_dp_tx_completion_handler(struct ath12k_base *ab, int ring_id)
 
 		desc_params.mac_id = tx_desc->mac_id;
 		desc_params.skb = tx_desc->skb;
+		desc_params.skb_ext_desc = tx_desc->skb_ext_desc;
 
 		/* Release descriptor as soon as extracting necessary info
 		 * to reduce contention
-- 
2.34.1