Messages in this thread Patch in this message | | | Subject | Re: [RFC][PATCH] tracing/module: Move tracepoint out of module.h | From | Eric Dumazet <> | Date | Thu, 29 Mar 2012 06:22:44 +0200 |
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Le mercredi 01 février 2012 à 17:18 +1030, Rusty Russell a écrit :
> > +void __module_get(struct module *module) > +{ > + if (module) { > + preempt_disable(); > + __this_cpu_inc(module->refptr->incs); > + trace_module_get(module, _RET_IP_); > + preempt_enable(); > + } > +} > +EXPORT_SYMBOL(__module_get); > +
Hi Rusty
I am wondering why preempt_disable()/preempt_enable() is needed in this code.
this_cpu_inc(module->refptr->incs) is preempt safe...
diff --git a/kernel/module.c b/kernel/module.c index 78ac6ec..7dc88b3 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -907,10 +907,8 @@ static struct module_attribute modinfo_refcnt = void __module_get(struct module *module) { if (module) { - preempt_disable(); - __this_cpu_inc(module->refptr->incs); + this_cpu_inc(module->refptr->incs); trace_module_get(module, _RET_IP_); - preempt_enable(); } } EXPORT_SYMBOL(__module_get); @@ -920,15 +918,11 @@ bool try_module_get(struct module *module) bool ret = true; if (module) { - preempt_disable(); - if (likely(module_is_live(module))) { - __this_cpu_inc(module->refptr->incs); + this_cpu_inc(module->refptr->incs); trace_module_get(module, _RET_IP_); } else ret = false; - - preempt_enable(); } return ret; } @@ -937,15 +931,13 @@ EXPORT_SYMBOL(try_module_get); void module_put(struct module *module) { if (module) { - preempt_disable(); smp_wmb(); /* see comment in module_refcount */ - __this_cpu_inc(module->refptr->decs); + this_cpu_inc(module->refptr->decs); trace_module_put(module, _RET_IP_); /* Maybe they're waiting for us to drop reference? */ if (unlikely(!module_is_live(module))) wake_up_process(module->waiter); - preempt_enable(); } } EXPORT_SYMBOL(module_put);
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