[PATCH ath-next] wifi: ath9k: unmap DMA and free skb for stale TX buffers on queue drain

[Rosen Penev <rosenp@gmail.com>]

When draining a TX queue (e.g. on device removal or reset), stale
ath_buf descriptors were returned directly to the free pool via
ath_tx_return_buffer without unmapping their DMA buffers or freeing
their associated skbs. This leaks both DMA API resources and socket
buffer memory.

Unmap the DMA buffer and free the skb before returning the buffer
to the pool.

Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/net/wireless/ath/ath9k/xmit.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 89d8b3178784..89930eaf1fd3 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1884,8 +1884,17 @@ static void ath_drain_txq_list(struct ath_softc *sc, struct ath_txq *txq,
 		bf = list_first_entry(list, struct ath_buf, list);
 
 		if (bf->bf_state.stale) {
-			list_del(&bf->list);
+			struct sk_buff *skb = bf->bf_mpdu;
 
+			list_del(&bf->list);
+			if (bf->bf_buf_addr) {
+				dma_unmap_single(sc->dev, bf->bf_buf_addr,
+						 skb ? skb->len : 0,
+						 DMA_TO_DEVICE);
+				bf->bf_buf_addr = 0;
+			}
+			bf->bf_mpdu = NULL;
+			dev_kfree_skb_any(skb);
 			ath_tx_return_buffer(sc, bf);
 			continue;
 		}
-- 
2.55.0