Re: [PATCH 2/2] modprobe: handle built-in modules

[Michal Marek <mmarek@xxxxxxx>]

Alan Jenkins napsal(a):
> On 9/10/09, Michal Marek <mmarek@xxxxxxx> wrote:
>> The kernel installs a modules.builtin file listing all builtin
>> modules. Let depmod generate a modules.builtin.bin file and use
>> this in modprobe: If a module is not found in modules.dep or
>> modules.alias, check if the module is builtin and print
>> "builtin <module>" instead of trying to load anything.
>> It is done in this order to not slow down the common case.
>>
>> Signed-off-by: Michal Marek <mmarek@xxxxxxx>
> 
> Cool.  I've seen the problem this fixes a couple of times.
> 
> Hmm, the last time I saw this was in a debian initramfs.  I guess you
> know that modules.order and now modules.builtin need to be copied into
> the initramfs, so SuSE will do that.  Do update-initramfs (debian) and
> dracut (the new fedora initramfs project) know that?
> 
> Might we need more such files in future?  I guess the future-proof way
> is to copy modules.* into the initramfs staging directory before
> running depmod.
> 
>> @@ -1331,6 +1349,11 @@ int do_modprobe(char *modname,
>>  					  modname, 0, flags & mit_remove,
>>  					  &modoptions, &commands,
>>  					  &aliases, &blacklist);
>> +			/* builtin module? */
>> +			if (!aliases && module_builtin(dirname, modname) == 1) {
>> +				info("builtin %s\n", modname);
>> +				return 0;
>> +			}
>>  		}
>>  	}
> 
> It looks like "modprobe -r $builtin_module" will return success.  I
> think it should fail and print an error instead.  That would be
> analogous to the situation where a module cannot be unloaded because
> it is still in use.
> 
> Similarly "modprobe --first-time $builtin-module" should cause an error.

Agreed.


> I thought the "builtin" message was inconsistent at first, because
> "modprobe -v $module" is currently silent if $module is already
> loaded.  But I see it is useful because "lsmod" won't work for builtin
> modules.

I changed it to only print "builtin <module>" if --show-depends was
given, because it normally prints "insmod <module>" even for loaded
modules. See next email for the updated patch.

Michal
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