rtlwifi: Handle previous allocation failures when freeing device memory

commit 7f66c2f9 upstream.

Handle previous allocation failures when freeing device memory
Signed-off-by: Simon Graham <simon.graham@virtualcomputer.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/wireless/rtlwifi/pci.c

@@ -1155,10 +1155,12 @@ static void _rtl_pci_free_tx_ring(struct ieee80211_hw *hw,
 		ring->idx = (ring->idx + 1) % ring->entries;
 	}
 
-	pci_free_consistent(rtlpci->pdev,
-			    sizeof(*ring->desc) * ring->entries,
-			    ring->desc, ring->dma);
-	ring->desc = NULL;
+	if (ring->desc) {
+		pci_free_consistent(rtlpci->pdev,
+				    sizeof(*ring->desc) * ring->entries,
+				    ring->desc, ring->dma);
+		ring->desc = NULL;
+	}
 }
 
 static void _rtl_pci_free_rx_ring(struct rtl_pci *rtlpci)
@@ -1182,12 +1184,14 @@ static void _rtl_pci_free_rx_ring(struct rtl_pci *rtlpci)
 			kfree_skb(skb);
 		}
 
-		pci_free_consistent(rtlpci->pdev,
+		if (rtlpci->rx_ring[rx_queue_idx].desc) {
+			pci_free_consistent(rtlpci->pdev,
 				    sizeof(*rtlpci->rx_ring[rx_queue_idx].
 					   desc) * rtlpci->rxringcount,
 				    rtlpci->rx_ring[rx_queue_idx].desc,
 				    rtlpci->rx_ring[rx_queue_idx].dma);
-		rtlpci->rx_ring[rx_queue_idx].desc = NULL;
+			rtlpci->rx_ring[rx_queue_idx].desc = NULL;
+		}
 	}
 }