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DateWed, 22 Sep 2010 10:14:32 -0400
FromMathieu Desnoyers <>
SubjectRe: [PATCH 1/2] Add for_each_module iterator function v2
* Andi Kleen (andi@firstfloor.org) wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> This is a generic function to iterate over all modules.
> To be used in the next patch.
>
> v2: Use module_mutex instead of preempt disabling
>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
> 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..9e2a561 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;
> +
> + mutex_lock(&module_mutex);

I'm concerned about the following mutex dependency chain:

module_mutex -> jump_label_mutex (on module load)
jump_label_mutex -> module_mutex (on jump_label_update)

Actually, I think your module notifier is missing in your version. This
is why you don't see this dependency problem.

Mathieu

> + list_for_each_entry_rcu(mod, &modules, list)
> + op(mod, arg);
> + mutex_unlock(&module_mutex);
> +}
> +
> #ifdef CONFIG_SMP
>
> static inline void __percpu *mod_percpu(struct module *mod)
> --
> 1.7.1
>

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


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