SysFS 'module' params with CONFIG_MODULES=n

SysFS 'module' params with CONFIG_MODULES=n

[Tom Rini]

On 2.6.14, and probably newer, a system where CONFIG_MODULES=n
/sys/module/foo/parameters/param fails:

# cat /sys/module/tcp_bic/parameters/low_window
cat: /sys/module/tcp_bic/parameters/low_window: Permission denied

But just changing MODULES to y:

# cat /sys/module/tcp_bic/parameters/low_window
14

Is this intentional or fixable?  Just an observation right now, thanks.

-- 
Tom Rini
http://gate.crashing.org/~trini/

Re: SysFS 'module' params with CONFIG_MODULES=n

[Greg KH]

On Fri, Nov 11, 2005 at 08:32:20AM -0700, Tom Rini wrote:
> On 2.6.14, and probably newer, a system where CONFIG_MODULES=n
> /sys/module/foo/parameters/param fails:
> 
> # cat /sys/module/tcp_bic/parameters/low_window
> cat: /sys/module/tcp_bic/parameters/low_window: Permission denied
> 
> But just changing MODULES to y:
> 
> # cat /sys/module/tcp_bic/parameters/low_window
> 14
> 
> Is this intentional or fixable?  Just an observation right now, thanks.

Not intentional at all.  Did this work before 2.6.14?

thanks,

greg k-h

Re: SysFS 'module' params with CONFIG_MODULES=n

[Jason Wessel]

[-- Attachment #1: Type: text/plain, Size: 967 bytes --]

Greg KH wrote:
> On Fri, Nov 11, 2005 at 08:32:20AM -0700, Tom Rini wrote:
>   
>> On 2.6.14, and probably newer, a system where CONFIG_MODULES=n
>> /sys/module/foo/parameters/param fails:
>>
>> # cat /sys/module/tcp_bic/parameters/low_window
>> cat: /sys/module/tcp_bic/parameters/low_window: Permission denied
>>
>> But just changing MODULES to y:
>>
>> # cat /sys/module/tcp_bic/parameters/low_window
>> 14
>>
>> Is this intentional or fixable?  Just an observation right now, thanks.
>>     
>
> Not intentional at all.  Did this work before 2.6.14?
>
> thanks,
>
> greg k-h
>   
I am not sure when it stopped working.

I recommend the attached patch to kernel/params.c All the work was done 
to setup the file and maintain the file handles but the access functions 
were zeroed out due to the #ifdef.  Removing the #ifdef allows full 
access to all the parameters when CONFIG_MODULES=n.

signed off: Jason Wessel <jason.wessel@windriver.com>

Thanks,
Jason.





[-- Attachment #2: params_sysfs.patch --]
[-- Type: text/plain, Size: 802 bytes --]

Index: linux-2.6.14/kernel/params.c
===================================================================
--- linux-2.6.14.orig/kernel/params.c	2005-11-11 08:40:03.456317256 -0800
+++ linux-2.6.14/kernel/params.c	2005-11-12 11:43:00.439765632 -0800
@@ -618,8 +618,6 @@ static void __init param_sysfs_builtin(v
 
 
 /* module-related sysfs stuff */
-#ifdef CONFIG_MODULES
-
 #define to_module_attr(n) container_of(n, struct module_attribute, attr);
 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj);
 
@@ -676,13 +674,6 @@ static struct sysfs_ops module_sysfs_ops
 	.store = module_attr_store,
 };
 
-#else
-static struct sysfs_ops module_sysfs_ops = {
-	.show = NULL,
-	.store = NULL,
-};
-#endif
-
 static struct kobj_type module_ktype = {
 	.sysfs_ops =	&module_sysfs_ops,
 };