[PATCH] USB: add ability for usb-serial drivers to determine if their write urb is currently being used.
This removes a lot of racy and buggy code by trying to check the status of the urb.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/serial/ir-usb.c b/drivers/usb/serial/ir-usb.c
index 59f234d..937b2fd 100644
--- a/drivers/usb/serial/ir-usb.c
+++ b/drivers/usb/serial/ir-usb.c
@@ -341,10 +341,14 @@
if (count == 0)
return 0;
- if (port->write_urb->status == -EINPROGRESS) {
- dbg ("%s - already writing", __FUNCTION__);
+ spin_lock(&port->lock);
+ if (port->write_urb_busy) {
+ spin_unlock(&port->lock);
+ dbg("%s - already writing", __FUNCTION__);
return 0;
}
+ port->write_urb_busy = 1;
+ spin_unlock(&port->lock);
transfer_buffer = port->write_urb->transfer_buffer;
transfer_size = min(count, port->bulk_out_size - 1);
@@ -374,9 +378,10 @@
port->write_urb->transfer_flags = URB_ZERO_PACKET;
result = usb_submit_urb (port->write_urb, GFP_ATOMIC);
- if (result)
+ if (result) {
+ port->write_urb_busy = 0;
dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__, result);
- else
+ } else
result = transfer_size;
return result;
@@ -387,7 +392,8 @@
struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
dbg("%s - port %d", __FUNCTION__, port->number);
-
+
+ port->write_urb_busy = 0;
if (urb->status) {
dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
return;