Re: [PATCH 1/2] Add for_each_module iterator function

[Mathieu Desnoyers]

* Thomas Gleixner (tglx@xxxxxxxxxxxxx) wrote:
> 
> 
> On Wed, 22 Sep 2010, Andi Kleen wrote:
> 
> > From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> > 
> > This is a generic function to iterate over all modules.
> > To be used in the next patch.
> > 
> > Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> > ---
> >  include/linux/module.h |    1 +
> >  kernel/module.c        |   10 ++++++++++
> >  2 files changed, 11 insertions(+), 0 deletions(-)
> > 
> > diff --git a/include/linux/module.h b/include/linux/module.h
> > index 403ac26..809b6db 100644
> > --- a/include/linux/module.h
> > +++ b/include/linux/module.h
> > @@ -410,6 +410,7 @@ struct module *__module_address(unsigned long addr);
> >  bool is_module_address(unsigned long addr);
> >  bool is_module_percpu_address(unsigned long addr);
> >  bool is_module_text_address(unsigned long addr);
> > +void for_each_module(void (*op)(struct module *, void *arg), void *arg);
> >  
> >  static inline int within_module_core(unsigned long addr, struct module *mod)
> >  {
> > diff --git a/kernel/module.c b/kernel/module.c
> > index eba1341..b8fb3e6 100644
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -384,6 +384,16 @@ struct module *find_module(const char *name)
> >  }
> >  EXPORT_SYMBOL_GPL(find_module);
> >  
> > +void for_each_module(void (*op)(struct module *, void *arg), void *arg)
> > +{
> > +	struct module *mod;
> > +
> > +	preempt_disable();
> 
>   That wants rcu_read_lock()

Then we might need to add synchronize_rcu() call when modules are
unloaded. For now, there is only synchronize_sched().

Mathieu

> 
> > +	list_for_each_entry_rcu(mod, &modules, list)
> > +		op(mod, arg);
> > +	preempt_enable();
> 
> Thanks,
> 
> 	tglx

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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