On 08/18, Takashi Iwai wrote:
>
> At Mon, 18 Aug 2014 14:22:17 +0200,
> Oleg Nesterov wrote:
> >
> > On 08/18, Takashi Iwai wrote:
> > >
> > > #define module_long_probe_init(initfn) \
> > > static int _long_probe_##initfn(void *arg) \
> > > { \
> > > module_put_and_exit(initfn()); \
> > > return 0; \
> > > } \
> > > static int __init __long_probe_##initfn(void) \
> > > { \
> > > struct task_struct *__init_thread = \
> > > kthread_create(_long_probe_##initfn, \
> > > NULL, #initfn); \
> > > if (IS_ERR(__init_thread)) \
> > > return PTR_ERR(__init_thread); \
> > > __module_get(THIS_MODULE); \
> > > wake_up_process(__init_thread); \
> > > return 0; \
> > > } \
> > > module_init(__long_probe_##initfn)
> > >
> > > ... and module_exit() remains identical as the normal version.
> >
> > Aaaah. This is not true, module_exit() should not call exitfn() if initfn()
> > fails... So _long_probe_##initfn() needs to save the error code which should
> > be checked by module_exit().
>
> Oh, right. So we need a reference in the module exit path in anyway,
We only need to save the error code,
static int _long_probe_retval;
static int _long_probe_##initfn(void *arg)
{
_long_probe_retval = initfn();
module_put_and_exit(0); /* noreturn */
}
static void __long_probe_##exitfn(void)
{
if (!_long_probe_retval)
exitfn();
}
> and Luis' version might be shorter in the end.
I dont't think that "shorter" does matter in this case. The real difference
is sys_delete_module() behaviour if it is called before initfn() completes.
And, again, I do not really know which version is better.
Oleg.
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