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[PATCH] USB: add ability for usb-serial drivers to determine if their write urb is currently being used.

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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>
This commit is contained in:
Greg Kroah-Hartman
2005-04-23 12:49:16 -07:00
parent f4df0e334a
commit 507ca9bc04
10 changed files with 85 additions and 46 deletions
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13
drivers/usb/serial/safe_serial.c
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@ -299,10 +299,14 @@ static int safe_write (struct usb_serial_port *port, const unsigned char *buf, i
dbg ("%s - write request of 0 bytes", __FUNCTION__);
return (0);
}
if (port->write_urb->status == -EINPROGRESS) {
dbg ("%s - already writing", __FUNCTION__);
return (0);
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);
packet_length = port->bulk_out_size; // get max packetsize
@ -354,6 +358,7 @@ static int safe_write (struct usb_serial_port *port, const unsigned char *buf, i
#endif
port->write_urb->dev = port->serial->dev;
if ((result = usb_submit_urb (port->write_urb, GFP_KERNEL))) {
port->write_urb_busy = 0;
err ("%s - failed submitting write urb, error %d", __FUNCTION__, result);
return 0;
}
@ -368,7 +373,7 @@ static int safe_write_room (struct usb_serial_port *port)
dbg ("%s", __FUNCTION__);
if (port->write_urb->status != -EINPROGRESS)
if (port->write_urb_busy)
room = port->bulk_out_size - (safe ? 2 : 0);
if (room) {