USB: serial: make minor allocation dynamic

This moves the allocation of minor device numbers from a static array to
be dynamic, using the idr interface.  This means that you could
potentially get "gaps" in a minor number range for a single USB serial
device with multiple ports, but all should still work properly.

We remove the 'minor' field from the usb_serial structure, as it no
longer makes any sense for it (use the field in the usb_serial_port
structure if you really want to know this number), and take the fact
that we were overloading a number in this field to determine if we had
initialized the minor numbers or not, and just use a flag variable
instead.

Note, we still have the limitation of 255 USB to serial devices in the
system, as that is all we are registering with the TTY layer at this
point in time.

Tested-by: Tobias Winter <tobias@linuxdingsda.de>
Reviewed-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c
index 1b811022f1a1..afb50eab2049 100644
--- a/drivers/usb/serial/console.c
+++ b/drivers/usb/serial/console.c
@@ -108,18 +108,18 @@ static int usb_console_setup(struct console *co, char *options)
 	 * no need to check the index here: if the index is wrong, console
 	 * code won't call us
 	 */
-	serial = usb_serial_get_by_index(co->index);
-	if (serial == NULL) {
+	port = usb_serial_port_get_by_minor(co->index);
+	if (port == NULL) {
 		/* no device is connected yet, sorry :( */
 		pr_err("No USB device connected to ttyUSB%i\n", co->index);
 		return -ENODEV;
 	}
+	serial = port->serial;
 
 	retval = usb_autopm_get_interface(serial->interface);
 	if (retval)
 		goto error_get_interface;
 
-	port = serial->port[co->index - serial->minor];
 	tty_port_tty_set(&port->port, NULL);
 
 	info->port = port;