Messages in this thread | | | Date | Tue, 28 Mar 2023 14:52:02 +0200 | From | Petr Mladek <> | Subject | Re: union: was: Re: [PATCH printk v1 05/18] printk: Add non-BKL console basic infrastructure |
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On Tue 2023-03-28 11:48:06, John Ogness wrote: > On 2023-03-28, Petr Mladek <pmladek@suse.com> wrote: > >> A compilation check would be nice. Is that possible? > > > > I think the following might do the trick: > > > > static_assert(sizeof(struct cons_state) == sizeof(atomic_long_t)); > > I never realized the kernel code was allowed to have that. But it is > everywhere! :-) Thanks. I've added and tested the following: > > /* > * The nbcon_state struct is used to easily create and interpret values that > * are stored in the console.nbcon_state variable. Make sure this struct stays > * within the size boundaries of that atomic variable's underlying type in > * order to avoid any accidental truncation. > */ > static_assert(sizeof(struct nbcon_state) <= sizeof(long)); > > Note that I am checking against sizeof(long), the underlying variable > type. We probably shouldn't assume sizeof(atomic_long_t) is always > sizeof(long).
Makes sense and looks good to me.
Best Regards, Petr
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