mac80211: fix memory accounting with A-MSDU aggregation

skb->truesize can change due to memory reallocation or when adding extra
fragments. Adjust fq->memory_usage accordingly
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -3221,6 +3221,7 @@ static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata,
 	u8 max_subframes = sta->sta.max_amsdu_subframes;
 	int max_frags = local->hw.max_tx_fragments;
 	int max_amsdu_len = sta->sta.max_amsdu_len;
+	int orig_truesize;
 	__be16 len;
 	void *data;
 	bool ret = false;
@@ -3261,6 +3262,7 @@ static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata,
 	if (!head || skb_is_gso(head))
 		goto out;
 
+	orig_truesize = head->truesize;
 	orig_len = head->len;
 
 	if (skb->len + head->len > max_amsdu_len)
@@ -3318,6 +3320,7 @@ static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata,
 	*frag_tail = skb;
 
 out_recalc:
+	fq->memory_usage += head->truesize - orig_truesize;
 	if (head->len != orig_len) {
 		flow->backlog += head->len - orig_len;
 		tin->backlog_bytes += head->len - orig_len;