macvtap: Destroy minor_idr on module_exit

Destroy minor_idr on module_exit, reclaiming the allocated memory.

This was detected by the following semantic patch (written by Luis Rodriguez
<mcgrof@suse.com>)
<SmPL>
@ defines_module_init @
declarer name module_init, module_exit;
declarer name DEFINE_IDR;
identifier init;
@@

module_init(init);

@ defines_module_exit @
identifier exit;
@@

module_exit(exit);

@ declares_idr depends on defines_module_init && defines_module_exit @
identifier idr;
@@

DEFINE_IDR(idr);

@ on_exit_calls_destroy depends on declares_idr && defines_module_exit @
identifier declares_idr.idr, defines_module_exit.exit;
@@

exit(void)
{
 ...
 idr_destroy(&idr);
 ...
}

@ missing_module_idr_destroy depends on declares_idr && defines_module_exit && !on_exit_calls_destroy @
identifier declares_idr.idr, defines_module_exit.exit;
@@

exit(void)
{
 ...
 +idr_destroy(&idr);
}
</SmPL>
Signed-off-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/macvtap.c

@@ -1294,6 +1294,7 @@ static void macvtap_exit(void)
 	class_unregister(macvtap_class);
 	cdev_del(&macvtap_cdev);
 	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
+	idr_destroy(&minor_idr);
 }
 module_exit(macvtap_exit);