* Re: Non-__init functions calling __init functions
@ 2003-03-20 16:15 Andrzej Krzysztofowicz
2003-03-20 16:23 ` Stuart MacDonald
0 siblings, 1 reply; 6+ messages in thread
From: Andrzej Krzysztofowicz @ 2003-03-20 16:15 UTC (permalink / raw)
To: kernel list; +Cc: stuartm
> This is always a bug isn't it?
... unless they are guaranteed to be called in the init context only.
Andrzej
--
=======================================================================
Andrzej M. Krzysztofowicz ankry@mif.pg.gda.pl
phone (48)(58) 347 14 61
Faculty of Applied Phys. & Math., Gdansk University of Technology
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Non-__init functions calling __init functions
2003-03-20 16:15 Non-__init functions calling __init functions Andrzej Krzysztofowicz
@ 2003-03-20 16:23 ` Stuart MacDonald
2003-03-20 16:32 ` Andrzej Krzysztofowicz
0 siblings, 1 reply; 6+ messages in thread
From: Stuart MacDonald @ 2003-03-20 16:23 UTC (permalink / raw)
To: Andrzej Krzysztofowicz, kernel list
From: "Andrzej Krzysztofowicz" <ankry@green.mif.pg.gda.pl>
> From: "Stuart MacDonald" <stuartm@connecttech.com>
> > This is always a bug isn't it?
>
> ... unless they are guaranteed to be called in the init context only.
In which case those functions should also be marked __init so they can
be reclaimed, correct? So it's the reciprocal bug.
..Stu
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Non-__init functions calling __init functions
2003-03-20 16:23 ` Stuart MacDonald
@ 2003-03-20 16:32 ` Andrzej Krzysztofowicz
2003-03-20 17:01 ` Chris Friesen
0 siblings, 1 reply; 6+ messages in thread
From: Andrzej Krzysztofowicz @ 2003-03-20 16:32 UTC (permalink / raw)
To: Stuart MacDonald; +Cc: Andrzej Krzysztofowicz, kernel list
> From: "Andrzej Krzysztofowicz" <ankry@green.mif.pg.gda.pl>
> > From: "Stuart MacDonald" <stuartm@connecttech.com>
> > > This is always a bug isn't it?
> >
> > ... unless they are guaranteed to be called in the init context only.
>
> In which case those functions should also be marked __init so they can
> be reclaimed, correct? So it's the reciprocal bug.
Not always possible.
__init A() {
...
}
__exit B() {
...
}
C() {
...
A();
...
#ifdef MODULE
B();
#endif
...
}
C cannot be marked __init for #define MODULE case. Even if it is called only
by some __init code. I can imagine other similar situations.
However it is not your case probably.
--
=======================================================================
Andrzej M. Krzysztofowicz ankry@mif.pg.gda.pl
phone (48)(58) 347 14 61
Faculty of Applied Phys. & Math., Gdansk University of Technology
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Non-__init functions calling __init functions
2003-03-20 16:32 ` Andrzej Krzysztofowicz
@ 2003-03-20 17:01 ` Chris Friesen
2003-03-21 9:10 ` Andrzej Krzysztofowicz
0 siblings, 1 reply; 6+ messages in thread
From: Chris Friesen @ 2003-03-20 17:01 UTC (permalink / raw)
To: Andrzej Krzysztofowicz; +Cc: Stuart MacDonald, kernel list
Andrzej Krzysztofowicz wrote:
> Not always possible.
>
> __init A() {
> ...
> }
>
> __exit B() {
> ...
> }
>
> C() {
> ...
> A();
> ...
> #ifdef MODULE
> B();
> #endif
> ...
> }
>
> C cannot be marked __init for #define MODULE case. Even if it is called only
> by some __init code. I can imagine other similar situations.
I thought that in the case of modules, __init is a noop? At least, that's what
this page says
http://www.netfilter.org/unreliable-guides/kernel-hacking/routines-init.html
So if MODULE is defined, it doesn't matter if C is labelled as __init or not,
and if it is not defined, it *should* be labelled as __init since it is itself
calling __init code.
Chris
--
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Nortel Networks | work: (613) 765-0557
3500 Carling Avenue | fax: (613) 765-2986
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Non-__init functions calling __init functions
2003-03-20 17:01 ` Chris Friesen
@ 2003-03-21 9:10 ` Andrzej Krzysztofowicz
0 siblings, 0 replies; 6+ messages in thread
From: Andrzej Krzysztofowicz @ 2003-03-21 9:10 UTC (permalink / raw)
To: Chris Friesen; +Cc: Andrzej Krzysztofowicz, Stuart MacDonald, kernel list
> Andrzej Krzysztofowicz wrote:
>
> > Not always possible.
> >
> > __init A() {
> > ...
> > }
> >
> > __exit B() {
> > ...
> > }
> >
> > C() {
> > ...
> > A();
> > ...
> > #ifdef MODULE
> > B();
> > #endif
> > ...
> > }
> >
> > C cannot be marked __init for #define MODULE case. Even if it is called only
> > by some __init code. I can imagine other similar situations.
>
> I thought that in the case of modules, __init is a noop? At least, that's what
> this page says
Currently - yes.
But I heard about patches that make __init usefull in modular case.
Why break them ?
> http://www.netfilter.org/unreliable-guides/kernel-hacking/routines-init.html
>
> So if MODULE is defined, it doesn't matter if C is labelled as __init or not,
> and if it is not defined, it *should* be labelled as __init since it is itself
> calling __init code.
Safely the following can be added:
+ #ifndef MODULE
+ __init
+ #endif
C() {
But I heard that our policy is avoiding extra #ifdefs if possible...
AFAIR, some __init functions were called (in 2.4 scsi code; I didn't check
newer code) indirectly, by pointers to them, from non __init code. It is
more dificult to detect such cases.
--
=======================================================================
Andrzej M. Krzysztofowicz ankry@mif.pg.gda.pl
phone (48)(58) 347 14 61
Faculty of Applied Phys. & Math., Gdansk University of Technology
^ permalink raw reply [flat|nested] 6+ messages in thread
* Non-__init functions calling __init functions
@ 2003-03-20 16:03 Stuart MacDonald
0 siblings, 0 replies; 6+ messages in thread
From: Stuart MacDonald @ 2003-03-20 16:03 UTC (permalink / raw)
To: linux-kernel
This is always a bug isn't it?
A quick check shows that the following files have non-__init functions
calling __init init_idle() in 2.5.65:
arch/ppc/kernel/smp.c
arch/um/kernel/smp.c
arch/mips/kernel/process.c
arch/mips64/kernel/process.c
arch/parisc/kernel/smp.c
arch/s390x/kernel/smp.c
arch/s390/kernel/smp.c
..Stu
^ permalink raw reply [flat|nested] 6+ messages in thread
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2003-03-20 16:15 Non-__init functions calling __init functions Andrzej Krzysztofowicz
2003-03-20 16:23 ` Stuart MacDonald
2003-03-20 16:32 ` Andrzej Krzysztofowicz
2003-03-20 17:01 ` Chris Friesen
2003-03-21 9:10 ` Andrzej Krzysztofowicz
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2003-03-20 16:03 Stuart MacDonald
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