char: lp: use first unused lp number while registering

When the parallel port is usb based and the lp attaches to it based on
LP_PARPORT_AUTO, we do get /dev/lp0 and when we remove the usb device
/dev/lp0 is unregistered. But if we now reconnect the usb device we get
/dev/lp1, another disconnection and reconnection and we get /dev/lp2.

Use the port number array to find the first unused lp number and use
that to register the lp device with the parallel port.

Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index e21ed4007d0f..0e081f521f51 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -958,7 +958,11 @@ static void lp_attach(struct parport *port)
                         printk(KERN_INFO "lp: ignoring parallel port (max. %d)\n",LP_NO);
                         return;
                 }
-                if (!lp_register(lp_count, port))
+                for (i = 0; i < LP_NO; i++)
+                        if (port_num[i] == -1)
+                                break;
+
+                if (!lp_register(i, port))
                         lp_count++;
                 break;