[PATCH] Fix error message display for rmmod

[Dan Fandrich]

On Sun, Sep 12, 2010 at 04:59:14PM +0200, Denys Vlasenko wrote:
> On Thu, Sep 9, 2010 at 10:14 PM, Dan Fandrich <dan at coneharvesters.com> wrote:
> > Previously, rmmod would display an error message when the module
> > WAS removed,
> 
> Can't reproduce this. Can you give exact steps how to make it happen?

I don't have to do anything special to make rmmod say nothing when it
fails to remove a module. But it looks like modules.dep et. al. must not
exist in order for rmmod to complain when it DOES remove a module (i.e.
/lib/modules/`uname -r`/ must exist but be empty). On a defconfig busybox
on x86:

$ sudo ./busybox rmmod NON_LOADED_MODULE  # Should give error, but doesn't
$ sudo ./busybox insmod qnx4.ko
$ sudo ./busybox rmmod qnx4     # Gives error when it shouldn't
rmmod: module 'qnx4' not found
$ sudo ./busybox rmmod qnx4		# This time should give error but doesn't
$

> > and would display no error when the module WAS NOT removed.
> 
> This seems to be a feature. MODPROBE_SMALL is making some
> simplifying assumptions, one of them is that "rmmod == modprobe -r".
> And "modprobe -r NON_LOADED_MODULE" does not error out.

modprobe from module-init-tools does show an error message if
NON_LOADED_MODULE is also not found in modules.dep (this is assuming
modules.dep exists or it gives another error):

$ sudo modprobe -r xyzzy
FATAL: Module xyzzy not found.
$

It does not show anything if the modules is found in modules.dep,
even if it's not loaded:

$ sudo modprobe -r qnx4
$ sudo modprobe -r qnx4
$

>>> Dan