mwifiex: improve error path handling in usb.c

skb allocated during initialisation is reused for receiving
commands/events by USB interface. We miss to reset skb->data in
failure cases. This patch takes care of it.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kiran Divekar <dkiran@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/usb.c

@@ -49,6 +49,7 @@ static int mwifiex_usb_recv(struct mwifiex_adapter *adapter,
 	struct device *dev = adapter->dev;
 	u32 recv_type;
 	__le32 tmp;
+	int ret;
 
 	if (adapter->hs_activated)
 		mwifiex_process_hs_config(adapter);
@@ -69,16 +70,19 @@ static int mwifiex_usb_recv(struct mwifiex_adapter *adapter,
 		case MWIFIEX_USB_TYPE_CMD:
 			if (skb->len > MWIFIEX_SIZE_OF_CMD_BUFFER) {
 				dev_err(dev, "CMD: skb->len too large\n");
-				return -1;
+				ret = -1;
+				goto exit_restore_skb;
 			} else if (!adapter->curr_cmd) {
 				dev_dbg(dev, "CMD: no curr_cmd\n");
 				if (adapter->ps_state == PS_STATE_SLEEP_CFM) {
 					mwifiex_process_sleep_confirm_resp(
 							adapter, skb->data,
 							skb->len);
-					return 0;
+					ret = 0;
+					goto exit_restore_skb;
 				}
-				return -1;
+				ret = -1;
+				goto exit_restore_skb;
 			}
 
 			adapter->curr_cmd->resp_skb = skb;
@@ -87,7 +91,8 @@ static int mwifiex_usb_recv(struct mwifiex_adapter *adapter,
 		case MWIFIEX_USB_TYPE_EVENT:
 			if (skb->len < sizeof(u32)) {
 				dev_err(dev, "EVENT: skb->len too small\n");
-				return -1;
+				ret = -1;
+				goto exit_restore_skb;
 			}
 			skb_copy_from_linear_data(skb, &tmp, sizeof(u32));
 			adapter->event_cause = le32_to_cpu(tmp);
@@ -95,7 +100,8 @@ static int mwifiex_usb_recv(struct mwifiex_adapter *adapter,
 
 			if (skb->len > MAX_EVENT_SIZE) {
 				dev_err(dev, "EVENT: event body too large\n");
-				return -1;
+				ret = -1;
+				goto exit_restore_skb;
 			}
 
 			memcpy(adapter->event_body, skb->data +
@@ -124,6 +130,12 @@ static int mwifiex_usb_recv(struct mwifiex_adapter *adapter,
 	}
 
 	return -EINPROGRESS;
+
+exit_restore_skb:
+	/* The buffer will be reused for further cmds/events */
+	skb_push(skb, INTF_HEADER_LEN);
+
+	return ret;
 }
 
 static void mwifiex_usb_rx_complete(struct urb *urb)