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path: root/drivers/usb/serial/generic.c
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Diffstat (limited to 'drivers/usb/serial/generic.c')
-rw-r--r--drivers/usb/serial/generic.c15
1 files changed, 4 insertions, 11 deletions
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 63b43308e160..9756b5c22d94 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -259,22 +259,15 @@ static int usb_serial_generic_write_start(struct usb_serial_port *port)
259 int result; 259 int result;
260 int count; 260 int count;
261 unsigned long flags; 261 unsigned long flags;
262 bool start_io;
263 262
264 /* Atomically determine whether we can and need to start a USB
265 * operation. */
266 spin_lock_irqsave(&port->lock, flags); 263 spin_lock_irqsave(&port->lock, flags);
267 if (port->write_urb_busy) 264 if (port->write_urb_busy || !kfifo_len(&port->write_fifo)) {
268 start_io = false; 265 spin_unlock_irqrestore(&port->lock, flags);
269 else { 266 return 0;
270 start_io = (kfifo_len(&port->write_fifo) != 0);
271 port->write_urb_busy = start_io;
272 } 267 }
268 port->write_urb_busy = 1;
273 spin_unlock_irqrestore(&port->lock, flags); 269 spin_unlock_irqrestore(&port->lock, flags);
274 270
275 if (!start_io)
276 return 0;
277
278 data = port->write_urb->transfer_buffer; 271 data = port->write_urb->transfer_buffer;
279 count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock); 272 count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
280 usb_serial_debug_data(debug, &port->dev, __func__, count, data); 273 usb_serial_debug_data(debug, &port->dev, __func__, count, data);