[Newbie-warning] MOD_INC_USE_COUNT usage

[Newbie-warning] MOD_INC_USE_COUNT usage

[Tim Cambrant]

With the high risk of being flamed, I send this to LKML. Feel free
to tell me not to if this is a huge no-no, and it won't happen
again.

I was studying some of the warnings that appears when compiling
2.6.1-mm3, and one common warning is the MOD_INC_USE_COUNT macro
being used. Apparently it's deprecated, but if that's the case,
why is it still being used in the kernel?

I googled a bit and found a few discussions about the issue
(mostly concerning the /mm-subsystem) where some people found
it okay to just remove the call to MOD_INC_USE_COUNT totally,
since it is totally unnecessary under 2.5 (and under 2.6 too,
I presume). Since the discussions provided a lot of contradictions
and no solution, I thought asking a question to someone who has
an idea of what this is about might be a good thing.

I'm not asking you to remove this call, but I do want to know
why it shouldn't be removed and what is being done to replace
a function (or macro... whatever it is) that is deprecated. Any
explanations would be gratefully accepted. Thank you.

Since I'm no kernel-hacker (and not much of a coder at all)
don't expect me to understand a lot of jargon, but this question
is being asked because I'm really interested in understanding
the Linux kernel.

So, why shouldn't this patch be applied?:

--- drivers/ide/pci/generic.c.orig      2004-01-14 17:52:35.000000000 +0100
+++ drivers/ide/pci/generic.c   2003-11-24 13:54:01.000000000 +0100
@@ -121,6 +121,7 @@ static int __devinit generic_init_one(st
		return 1;
	}
	ide_setup_pci_device(dev, d);
+	MOD_INC_USE_COUNT;
	return 0;
 }


                Tim Cambrant

Re: [Newbie-warning] MOD_INC_USE_COUNT usage

[Krzysztof Halasa]

Tim Cambrant <tim@cambrant.com> writes:

> So, why shouldn't this patch be applied?:
>
> --- drivers/ide/pci/generic.c.orig      2004-01-14 17:52:35.000000000 +0100
> +++ drivers/ide/pci/generic.c   2003-11-24 13:54:01.000000000 +0100
> @@ -121,6 +121,7 @@ static int __devinit generic_init_one(st
> 		return 1;
> 	}
> 	ide_setup_pci_device(dev, d);
> +	MOD_INC_USE_COUNT;
> 	return 0;
>  }

It isn't that easy - the module must be marked as being in use this
way or (preferably) another.
-- 
Krzysztof Halasa, B*FH

Re: [Newbie-warning] MOD_INC_USE_COUNT usage

[Yury V. Umanets]

On Wed, 2004-01-14 at 21:25, Krzysztof Halasa wrote:
> Tim Cambrant <tim@cambrant.com> writes:
> 
> > So, why shouldn't this patch be applied?:
> >
> > --- drivers/ide/pci/generic.c.orig      2004-01-14 17:52:35.000000000 +0100
> > +++ drivers/ide/pci/generic.c   2003-11-24 13:54:01.000000000 +0100
> > @@ -121,6 +121,7 @@ static int __devinit generic_init_one(st
> > 		return 1;
> > 	}
> > 	ide_setup_pci_device(dev, d);
> > +	MOD_INC_USE_COUNT;
> > 	return 0;
> >  }
> 
> It isn't that easy - the module must be marked as being in use this
> way or (preferably) another.

Hello,

As I can see, this is really redundant to have a MOD_INC_USE_COUNT for
almost all the modules. But this should be checked carefully before
removing ;)


-- 
umka