some 2.5.66 issues

some 2.5.66 issues

[Ronald Bultje]

Hey,

people are asking for comments on 2.5.x, so here goes. gcc-2.96, RH-7.3,
kernel 2.5.66 with module-init-tools-0.9.10.

* the smc-ultra networking module doesn't work. On any operation, it
returns "Device or Resource Busy".
* module_request() is still broken - it returns 0 but the specified
module isn't loaded

Now, something more problematic. I'm being told to use try_module_get()
instead of MOD_INC_USE_COUNT. Cool. Somehow, it returns 1. I had a look
at the code in linux/module.h and am a bit confused:

--
static inline int try_module_get(struct module *module) 
{ 
        int ret = 1; 
                                                                                 
        if (module) { 
                unsigned int cpu = get_cpu(); 
                if (likely(module_is_live(module))) 
                        local_inc(&module->ref[cpu].count); 
                else 
                        ret = 0; 
                put_cpu(); 
        } 
        return ret; 
}
--

Why does it only return 0 if the module is not alive? This sounds...
er... weird? Can someone please enlighten me?

Looking further:

--
/* Not Yet Implemented */ 
#define MODULE_AUTHOR(name) 
#define MODULE_DESCRIPTION(desc) 
#define MODULE_SUPPORTED_DEVICE(name) 
#define MODULE_PARM_DESC(var,desc)
--

No wonder modinfo doesn't show any info... Even worse, the only module
parameter thing that *does* work is MODULE_PARM...

--
/* DEPRECATED: Do not use. */ 
#define MODULE_PARM(var,type) \
struct obsolete_modparm __parm_##var \
__attribute__((section("__obsparm"))) \
{ __stringify(var), type };
--

Interesting. What's going on here?

Ronald

(please CC me any replies, I'm not subscribed)

-- 
Ronald Bultje <rbultje@ronald.bitfreak.net>

Re: some 2.5.66 issues

[Chris Friesen]

Ronald Bultje wrote:

> Now, something more problematic. I'm being told to use try_module_get()
> instead of MOD_INC_USE_COUNT. Cool. Somehow, it returns 1. I had a look
> at the code in linux/module.h and am a bit confused:

> Why does it only return 0 if the module is not alive? This sounds...
> er... weird? Can someone please enlighten me?

Presumably so you can treat the result as a boolean true/false value.

Chris



-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com

Re: some 2.5.66 issues

[mikpe]

On 29 Mar 2003 00:24:14 +0100, Ronald Bultje wrote:
>people are asking for comments on 2.5.x, so here goes. gcc-2.96, RH-7.3,
>kernel 2.5.66 with module-init-tools-0.9.10.
...
>* module_request() is still broken - it returns 0 but the specified
>module isn't loaded

To summarise: RH user-space, 2.5 kernel, modules don't autoload.

This is a well-known user-space (*) bug. Fix below.

(*) Well, unless "dropping /proc/ksyms for no good reason" counts
as a 2.5 kernel bug.

--- /etc/rc.d/rc.sysinit.~1~	2002-08-22 23:10:52.000000000 +0200
+++ /etc/rc.d/rc.sysinit	2003-01-14 03:04:57.000000000 +0100
@@ -334,7 +334,7 @@
     IN_INITLOG=
 fi
 
-if ! grep -iq nomodules /proc/cmdline 2>/dev/null && [ -f /proc/ksyms ]; then
+if ! grep -iq nomodules /proc/cmdline 2>/dev/null && [ -f /proc/modules ]; then
     USEMODULES=y
 fi