Re: [RFC PATCH v2 1/4] y2038: add 64bit time_t support in timeval for 32bit architecture

[Bamvor Zhang Jian]

Hi, John

On 07/09/2015 04:09 AM, John Stultz wrote:
> On Mon, Jun 29, 2015 at 7:23 AM, Bamvor Zhang Jian
> <bamvor.zhangjian@xxxxxxxxxx> wrote:
> > +int get_timeval64(struct timeval64 *tv,
> > +                  const struct __kernel_timeval __user *utv)
> > +{
> > +       struct __kernel_timeval ktv;
> > +       int ret;
> > +
> > +       ret = copy_from_user(&ktv, utv, sizeof(ktv));
> > +       if (ret)
> > +               return -EFAULT;
> > +
> > +       tv->tv_sec = ktv.tv_sec;
> > +       if (!IS_ENABLED(CONFIG_64BIT)
> > +#ifdef CONFIG_COMPAT
> > +          || is_compat_task()
> > +#endif
>
> These sorts of ifdefs are to be avoided inside of functions.

> Instead, it seems is_compat_task() should be defined to 0 in the
> !CONFIG_COMPAT case, so you can avoid the ifdefs and the compiler can
> still optimize it out.
I add this ifdef because I got compile failure on arm platform. This
file do not include the <linux/compat.h> directly. And in arm64,
compat.h is included implicitily.
So, I am not sure what I should do here. Include <linux/compat.h> in
this file directly or add a this check at the beginning of this file?

#ifndef is_compat_task
#define is_compat_task() (0)
#endif

> Otherwise this looks similar to a patch Baolin (cc'ed) has been working on.
Yes.

regards

bamvor
> thanks
> -john
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