ath9k: fix more-data flag for buffered multicast packets

The flag needs to be cleared for the last packet in the list, not the
first one. Fixes some issues with multicast packet loss for powersave
clients connected to an ath9k AP.

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/kernel/mac80211/patches/331-ath9k-fix-more-data-flag-for-buffered-multicast-pack.patch

@@ -0,0 +1,38 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sun, 23 Jul 2017 14:58:22 +0200
+Subject: [PATCH] ath9k: fix more-data flag for buffered multicast packets
+
+The flag needs to be cleared for the last packet in the list, not the
+first one. Fixes some issues with multicast packet loss for powersave
+clients connected to an ath9k AP.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/drivers/net/wireless/ath/ath9k/xmit.c
++++ b/drivers/net/wireless/ath/ath9k/xmit.c
+@@ -2451,7 +2451,6 @@ void ath_tx_cabq(struct ieee80211_hw *hw
+ 		.txq = sc->beacon.cabq
+ 	};
+ 	struct ath_tx_info info = {};
+-	struct ieee80211_hdr *hdr;
+ 	struct ath_buf *bf_tail = NULL;
+ 	struct ath_buf *bf;
+ 	LIST_HEAD(bf_q);
+@@ -2495,14 +2494,8 @@ void ath_tx_cabq(struct ieee80211_hw *hw
+ 	if (list_empty(&bf_q))
+ 		return;
+ 
+-	bf = list_first_entry(&bf_q, struct ath_buf, list);
+-	hdr = (struct ieee80211_hdr *) bf->bf_mpdu->data;
+-
+-	if (hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_MOREDATA)) {
+-		hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_MOREDATA);
+-		dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
+-			sizeof(*hdr), DMA_TO_DEVICE);
+-	}
++	bf = list_last_entry(&bf_q, struct ath_buf, list);
++	ath9k_set_moredata(sc, bf, false);
+ 
+ 	ath_txq_lock(sc, txctl.txq);
+ 	ath_tx_fill_desc(sc, bf, txctl.txq, 0);