net:CXGB4: fix leak if sk_buff is not used

[ Upstream commit 52bfcdd ]

An sk_buff is allocated to send a flow control message, but it's not
sent in all cases: in case the state is not appropiate to send it or if
it can't be enqueued.

In the first of these 2 cases, the sk_buff was discarded but not freed,
producing a memory leak.

Signed-off-by: Íñigo Huguet <ihuguet@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: ihuguet

drivers/net/ethernet/chelsio/cxgb4/sge.c

@@ -2559,12 +2559,12 @@ int cxgb4_ethofld_send_flowc(struct net_device *dev, u32 eotid, u32 tc)
 	spin_lock_bh(&eosw_txq->lock);
 	if (tc != FW_SCHED_CLS_NONE) {
 		if (eosw_txq->state != CXGB4_EO_STATE_CLOSED)
-			goto out_unlock;
+			goto out_free_skb;
 
 		next_state = CXGB4_EO_STATE_FLOWC_OPEN_SEND;
 	} else {
 		if (eosw_txq->state != CXGB4_EO_STATE_ACTIVE)
-			goto out_unlock;
+			goto out_free_skb;
 
 		next_state = CXGB4_EO_STATE_FLOWC_CLOSE_SEND;
 	}
@@ -2600,17 +2600,19 @@ int cxgb4_ethofld_send_flowc(struct net_device *dev, u32 eotid, u32 tc)
 		eosw_txq_flush_pending_skbs(eosw_txq);
 
 	ret = eosw_txq_enqueue(eosw_txq, skb);
-	if (ret) {
-		dev_consume_skb_any(skb);
-		goto out_unlock;
-	}
+	if (ret)
+		goto out_free_skb;
 
 	eosw_txq->state = next_state;
 	eosw_txq->flowc_idx = eosw_txq->pidx;
 	eosw_txq_advance(eosw_txq, 1);
 	ethofld_xmit(dev, eosw_txq);
 
-out_unlock:
+	spin_unlock_bh(&eosw_txq->lock);
+	return 0;
+
+out_free_skb:
+	dev_consume_skb_any(skb);
 	spin_unlock_bh(&eosw_txq->lock);
 	return ret;
 }