[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/omninet.c b/drivers/usb/serial/omninet.c
index b5f2c06..6a99ae1 100644
--- a/drivers/usb/serial/omninet.c
+++ b/drivers/usb/serial/omninet.c
@@ -254,10 +254,15 @@
dbg("%s - write request of 0 bytes", __FUNCTION__);
return (0);
}
- if (wport->write_urb->status == -EINPROGRESS) {
+
+ spin_lock(&port->lock);
+ if (port->write_urb_busy) {
+ spin_unlock(&port->lock);
dbg("%s - already writing", __FUNCTION__);
- return (0);
+ return 0;
}
+ port->write_urb_busy = 1;
+ spin_unlock(&port->lock);
count = (count > OMNINET_BULKOUTSIZE) ? OMNINET_BULKOUTSIZE : count;
@@ -275,9 +280,10 @@
wport->write_urb->dev = serial->dev;
result = usb_submit_urb(wport->write_urb, GFP_ATOMIC);
- if (result)
+ if (result) {
+ port->write_urb_busy = 0;
err("%s - failed submitting write urb, error %d", __FUNCTION__, result);
- else
+ } else
result = count;
return result;
@@ -291,7 +297,7 @@
int room = 0; // Default: no room
- if (wport->write_urb->status != -EINPROGRESS)
+ if (wport->write_urb_busy)
room = wport->bulk_out_size - OMNINET_HEADERLEN;
// dbg("omninet_write_room returns %d", room);
@@ -306,6 +312,7 @@
// dbg("omninet_write_bulk_callback, port %0x\n", port);
+ port->write_urb_busy = 0;
if (urb->status) {
dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
return;