drivers/char/misc.c: deprecated call register_chrdev, and 256 minor limit eliminated
PATCH 1/1 drivers/char/misc.c: deprecated call register_chrdev, and 256 minor limit eliminated
Dear Kernel Developers,
I have seen that drivers/char/misc.c already used the deprecated register_chrdev call and this limited the number of minors to 256.
I recetly asked for a misc minor number attribution for View-OS/kmview and Torben Mathiasen told me about this issue.
I propose this patch that eliminate both problems. With this patch misc allocates the entire major 10 and avoids the deprecated call.
These are just my 2 (euro) cents, I hope it can be useful.
renzo
Signature · 7 lines
============================================================================ Renzo Davoli | Dept. of Computer Science (NIC rd235, HAM IZ4DJE) | University of Bologna Tel. +39 051 2094501 | Mura Anteo Zamboni, 7 Fax. +39 051 2094510 | I-40127 Bologna ITALY Key fingerprint = A019 17E2 5562 06F6 77BB 2E93 1A01 F646 30EA B487 ============================================================================
char/misc.c renamed from char/misc.orig.c +28 -1
@@ -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);
On Thu, Sep 06, 2007 at 11:38:44AM +0200, Renzo Davoli wrote:
Dear Kernel Developers,
I have seen that drivers/char/misc.c already used the deprecated register_chrdev call and this limited the number of minors to 256.
I recetly asked for a misc minor number attribution for View-OS/kmview and Torben Mathiasen told me about this issue.
I propose this patch that eliminate both problems. With this patch misc allocates the entire major 10 and avoids the deprecated call.
These are just my 2 (euro) cents, I hope it can be useful.
renzo
Signature · 70 lines
============================================================================
Renzo Davoli | Dept. of Computer Science
(NIC rd235, HAM IZ4DJE) | University of Bologna
Tel. +39 051 2094501 | Mura Anteo Zamboni, 7
Fax. +39 051 2094510 | I-40127 Bologna ITALY
Key fingerprint = A019 17E2 5562 06F6 77BB 2E93 1A01 F646 30EA B487
============================================================================
--- drivers/char/misc.orig.c 2007-08-05 16:56:59.000000000 +0200
+++ 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);
--
============================================================================
Renzo Davoli | Dept. of Computer Science
(NIC rd235, HAM IZ4DJE) | University of Bologna
Tel. +39 051 2094501 | Mura Anteo Zamboni, 7
Fax. +39 051 2094510 | I-40127 Bologna ITALY
Key fingerprint = A019 17E2 5562 06F6 77BB 2E93 1A01 F646 30EA B487
============================================================================