Re: [PATCH] Module alias and device table support.

Rusty Russell
2003-02-03T02:17:39Z

In message <200302012302.h11N2R3U001433@eeyore.valparaiso.cl> you write:
> Rusty Russell <rusty@rustcorp.com.au> said:
>
> [...]
>
> > BTW, the reason for using the alias mechanism is that aliases are
> > useful in themselves: consider you write a "new_foo" driver, you can
> > do "MODULE_ALIAS("foo")" and so no userspace changes are neccessary.
> > module-init-tools 0.9.8 already supported this.
>
> May I respectfully disagree again?

Hi Horst,

Thoughtful and respecful criticism? I didn't think that was
allowed on linux-kernel any more? 8)

> This is fundamentally broken, as it takes away the possibility of me
> (sysadmin) to load foo or old_foo. I end up with an (useless) foo, and a
> new_foo that aliases for foo, and soon I'd have even_newer_foo masquerading
> as foo too, and all hell breaks loose. The effect is bloat over just
> deleting foo in the first place, as it can't be used at all now.

Well, "modprobe foo" will only give you the "new_foo" driver if (1) the
foo driver isn't found, and (2) the new driver author decides that
it's a valid replacement.

Whether (2) is ever justified, I'm happy leaving to the individual
author (I know, that makes me a wimp).

Consider another example: convenience aliases such as char-major-xxx.
Now, I'm not convinced they're a great idea anyway, but if people are
going to do this, I'd rather they did it in the kernel, rather than
some random userspace program.

I think the alias mechanism is valid, but you have a point about the
dangers, too.

Thoughts?
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.