From: Johan Hovold <jhovold@xxxxxxxxx>
Submit write urb if it is not already in use and we have buffered data.
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/usb/serial/generic.c | 15 ++++-----------
1 files changed, 4 insertions(+), 11 deletions(-)
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 63b4330..9756b5c 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)
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);
+ return 0;
}
+ port->write_urb_busy = 1;
spin_unlock_irqrestore(&port->lock, flags);
- if (!start_io)
- return 0;
-
data = port->write_urb->transfer_buffer;
count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
usb_serial_debug_data(debug, &port->dev, __func__, count, data);
--
1.7.1
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