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Commit 50a5f70c authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: serial: clean up generic write start busy test 



Submit write urb if it is not already in use and we have buffered data.

Signed-off-by: default avatarJohan Hovold <jhovold@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 1a1405e2

drivers/usb/serial/generic.c

+4 −11
Original line number Diff line number Diff line
@@ -259,21 +259,14 @@ static int usb_serial_generic_write_start(struct usb_serial_port *port) 
	int result;

	int count;

	unsigned long flags;

	bool start_io;



	/* Atomically determine whether we can and need to start a USB

	 * operation. */

	spin_lock_irqsave(&port->lock, flags);

	if (port->write_urb_busy)

		start_io = false;

	else {

		start_io = (kfifo_len(&port->write_fifo) != 0);

		port->write_urb_busy = start_io;

	}

	if (port->write_urb_busy || !kfifo_len(&port->write_fifo)) {

		spin_unlock_irqrestore(&port->lock, flags);



	if (!start_io)

		return 0;

	}

	port->write_urb_busy = 1;

	spin_unlock_irqrestore(&port->lock, flags);



	data = port->write_urb->transfer_buffer;

	count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);