iwl3945: fix bugs in txq freeing

When we free a txq that had no txb array allocated,
we still try to access it. Fix that, and also free
all SKBs that may be in the txb array (although it
can just be a single one).
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>

drivers/net/wireless/iwlwifi/iwl-3945.c

@@ -705,16 +705,18 @@ void iwl3945_hw_txq_free_tfd(struct iwl_priv *priv, struct iwl_tx_queue *txq)
 	for (i = 1; i < counter; i++) {
 		pci_unmap_single(dev, le32_to_cpu(tfd->tbs[i].addr),
 			 le32_to_cpu(tfd->tbs[i].len), PCI_DMA_TODEVICE);
-		if (txq->txb[txq->q.read_ptr].skb[0]) {
-			struct sk_buff *skb = txq->txb[txq->q.read_ptr].skb[0];
-			if (txq->txb[txq->q.read_ptr].skb[0]) {
-				/* Can be called from interrupt context */
+		if (txq->txb) {
+			struct sk_buff *skb;
+
+			skb = txq->txb[txq->q.read_ptr].skb[i - 1];
+
+			/* can be called from irqs-disabled context */
+			if (skb) {
 				dev_kfree_skb_any(skb);
-				txq->txb[txq->q.read_ptr].skb[0] = NULL;
+				txq->txb[txq->q.read_ptr].skb[i - 1] = NULL;
 			}
 		}
 	}
-	return ;
 }
 
 /**