From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934554AbXLPQ3Q (ORCPT ); Sun, 16 Dec 2007 11:29:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762209AbXLPQ3C (ORCPT ); Sun, 16 Dec 2007 11:29:02 -0500 Received: from lec.cs.unibo.it ([130.136.1.103]:33347 "EHLO lec.cs.unibo.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754860AbXLPQ3A (ORCPT ); Sun, 16 Dec 2007 11:29:00 -0500 Date: Sun, 16 Dec 2007 17:28:59 +0100 To: linux-kernel@vger.kernel.org Subject: [PATCH] misc driver: eliminate 256 minor limit & deprecated call register_chrdev Message-ID: <20071216162859.GA26191@cs.unibo.it> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.13 (2006-08-11) From: renzo@cs.unibo.it (Renzo Davoli) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I already posted this patch on September 9th but nobody cared. Is anybody interested in knowing that there is an old limit for misc device minors to 256, that we are terminating the minor numbers, and that there is a deprecated call in this code? drivers/char/misc.c: the deprecated call is register_chrdev and it limits the number of minors to 256. I propose this patch that eliminate both problems. With this patch misc allocates the entire major 10. This patch was designed for a previous version of the kernel code (2.6.22?), I have tested it today and applies to 2.6.24-rc5 with -12 lines offset. renzo Signed-off-by: Renzo Davoli --- a/drivers/char/misc.c 2007-08-05 16:56:59.000000000 +0200 +++ b/drivers/char/misc.c 2007-09-06 11:07:51.000000000 +0200 @@ -56,6 +56,8 @@ static LIST_HEAD(misc_list); static DEFINE_MUTEX(misc_mtx); +static struct cdev misc_cdev; + /* * Assigned numbers, used for dynamic minors */ @@ -273,6 +275,31 @@ EXPORT_SYMBOL(misc_register); EXPORT_SYMBOL(misc_deregister); +static int misc_register_chrdev(void) +{ + dev_t from=MKDEV(MISC_MAJOR,0); + int rv; + int err = -ENOMEM; + char *s; + + if ((rv=register_chrdev_region(from,MINORMASK,"misc")) != 0) + return rv; + + cdev_init(&misc_cdev, &misc_fops); + misc_cdev.owner=misc_fops.owner; + kobject_set_name(&misc_cdev.kobj, "%s", "misc"); + for (s = strchr(kobject_name(&misc_cdev.kobj),'/'); s; s = strchr(s, '/')) + *s = '!'; + err = cdev_add(&misc_cdev, from, MINORMASK); + if (err) + goto out; + return 0; +out: + kobject_put(&misc_cdev.kobj); + unregister_chrdev_region(from,MINORMASK); + return err; +} + static int __init misc_init(void) { #ifdef CONFIG_PROC_FS @@ -286,7 +313,7 @@ if (IS_ERR(misc_class)) return PTR_ERR(misc_class); - if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) { + if (misc_register_chrdev()) { printk("unable to get major %d for misc devices\n", MISC_MAJOR); class_destroy(misc_class);