net: usb: hso: use irqsave() in USB's complete callback

The USB completion callback does not disable interrupts while acquiring
the lock. We want to remove the local_irq_disable() invocation from
__usb_hcd_giveback_urb() and therefore it is required for the callback
handler to disable the interrupts while acquiring the lock.
The callback may be invoked either in IRQ or BH context depending on the
USB host controller.
Use the _irqsave() variant of the locking primitives.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/hso.c

@@ -999,6 +999,7 @@ static void read_bulk_callback(struct urb *urb)
 	struct hso_net *odev = urb->context;
 	struct net_device *net;
 	int result;
+	unsigned long flags;
 	int status = urb->status;
 
 	/* is al ok?  (Filip: Who's Al ?) */
@@ -1028,11 +1029,11 @@ static void read_bulk_callback(struct urb *urb)
 	if (urb->actual_length) {
 		/* Handle the IP stream, add header and push it onto network
 		 * stack if the packet is complete. */
-		spin_lock(&odev->net_lock);
+		spin_lock_irqsave(&odev->net_lock, flags);
 		packetizeRx(odev, urb->transfer_buffer, urb->actual_length,
 			    (urb->transfer_buffer_length >
 			     urb->actual_length) ? 1 : 0);
-		spin_unlock(&odev->net_lock);
+		spin_unlock_irqrestore(&odev->net_lock, flags);
 	}
 
 	/* We are done with this URB, resubmit it. Prep the USB to wait for
@@ -1193,6 +1194,7 @@ static void hso_std_serial_read_bulk_callback(struct urb *urb)
 {
 	struct hso_serial *serial = urb->context;
 	int status = urb->status;
+	unsigned long flags;
 
 	hso_dbg(0x8, "--- Got serial_read_bulk callback %02x ---\n", status);
 
@@ -1216,10 +1218,10 @@ static void hso_std_serial_read_bulk_callback(struct urb *urb)
 	if (serial->parent->port_spec & HSO_INFO_CRC_BUG)
 		fix_crc_bug(urb, serial->in_endp->wMaxPacketSize);
 	/* Valid data, handle RX data */
-	spin_lock(&serial->serial_lock);
+	spin_lock_irqsave(&serial->serial_lock, flags);
 	serial->rx_urb_filled[hso_urb_to_index(serial, urb)] = 1;
 	put_rxbuf_data_and_resubmit_bulk_urb(serial);
-	spin_unlock(&serial->serial_lock);
+	spin_unlock_irqrestore(&serial->serial_lock, flags);
 }
 
 /*
@@ -1502,12 +1504,13 @@ static void tiocmget_intr_callback(struct urb *urb)
 		DUMP(serial_state_notification,
 		     sizeof(struct hso_serial_state_notification));
 	} else {
+		unsigned long flags;
 
 		UART_state_bitmap = le16_to_cpu(serial_state_notification->
 						UART_state_bitmap);
 		prev_UART_state_bitmap = tiocmget->prev_UART_state_bitmap;
 		icount = &tiocmget->icount;
-		spin_lock(&serial->serial_lock);
+		spin_lock_irqsave(&serial->serial_lock, flags);
 		if ((UART_state_bitmap & B_OVERRUN) !=
 		   (prev_UART_state_bitmap & B_OVERRUN))
 			icount->parity++;
@@ -1530,7 +1533,7 @@ static void tiocmget_intr_callback(struct urb *urb)
 		   (prev_UART_state_bitmap & B_RX_CARRIER))
 			icount->dcd++;
 		tiocmget->prev_UART_state_bitmap = UART_state_bitmap;
-		spin_unlock(&serial->serial_lock);
+		spin_unlock_irqrestore(&serial->serial_lock, flags);
 		tiocmget->intr_completed = 1;
 		wake_up_interruptible(&tiocmget->waitq);
 	}
@@ -1852,6 +1855,7 @@ static void intr_callback(struct urb *urb)
 	struct hso_serial *serial;
 	unsigned char *port_req;
 	int status = urb->status;
+	unsigned long flags;
 	int i;
 
 	usb_mark_last_busy(urb->dev);
@@ -1879,7 +1883,7 @@ static void intr_callback(struct urb *urb)
 			if (serial != NULL) {
 				hso_dbg(0x1, "Pending read interrupt on port %d\n",
 					i);
-				spin_lock(&serial->serial_lock);
+				spin_lock_irqsave(&serial->serial_lock, flags);
 				if (serial->rx_state == RX_IDLE &&
 					serial->port.count > 0) {
 					/* Setup and send a ctrl req read on
@@ -1893,7 +1897,8 @@ static void intr_callback(struct urb *urb)
 					hso_dbg(0x1, "Already a read pending on port %d or port not open\n",
 						i);
 				}
-				spin_unlock(&serial->serial_lock);
+				spin_unlock_irqrestore(&serial->serial_lock,
+						       flags);
 			}
 		}
 	}
@@ -1920,6 +1925,7 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 {
 	struct hso_serial *serial = urb->context;
 	int status = urb->status;
+	unsigned long flags;
 
 	/* sanity check */
 	if (!serial) {
@@ -1927,9 +1933,9 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 		return;
 	}
 
-	spin_lock(&serial->serial_lock);
+	spin_lock_irqsave(&serial->serial_lock, flags);
 	serial->tx_urb_used = 0;
-	spin_unlock(&serial->serial_lock);
+	spin_unlock_irqrestore(&serial->serial_lock, flags);
 	if (status) {
 		handle_usb_error(status, __func__, serial->parent);
 		return;
@@ -1971,14 +1977,15 @@ static void ctrl_callback(struct urb *urb)
 	struct hso_serial *serial = urb->context;
 	struct usb_ctrlrequest *req;
 	int status = urb->status;
+	unsigned long flags;
 
 	/* sanity check */
 	if (!serial)
 		return;
 
-	spin_lock(&serial->serial_lock);
+	spin_lock_irqsave(&serial->serial_lock, flags);
 	serial->tx_urb_used = 0;
-	spin_unlock(&serial->serial_lock);
+	spin_unlock_irqrestore(&serial->serial_lock, flags);
 	if (status) {
 		handle_usb_error(status, __func__, serial->parent);
 		return;
@@ -1994,9 +2001,9 @@ static void ctrl_callback(struct urb *urb)
 	    (USB_DIR_IN | USB_TYPE_OPTION_VENDOR | USB_RECIP_INTERFACE)) {
 		/* response to a read command */
 		serial->rx_urb_filled[0] = 1;
-		spin_lock(&serial->serial_lock);
+		spin_lock_irqsave(&serial->serial_lock, flags);
 		put_rxbuf_data_and_resubmit_ctrl_urb(serial);
-		spin_unlock(&serial->serial_lock);
+		spin_unlock_irqrestore(&serial->serial_lock, flags);
 	} else {
 		hso_put_activity(serial->parent);
 		tty_port_tty_wakeup(&serial->port);