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From: Petr Mladek <pmladek@suse.com>
To: John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-fsdevel@vger.kernel.org
Subject: Re: union: was: Re: [PATCH printk v1 05/18] printk: Add non-BKL console basic infrastructure
Date: Tue, 28 Mar 2023 14:52:02 +0200	[thread overview]
Message-ID: <ZCLi8kWOdq8dwxSH@alley> (raw)
In-Reply-To: <87cz4tus9d.fsf@jogness.linutronix.de>

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

  reply	other threads:[~2023-03-28 12:53 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-02 19:56 [PATCH printk v1 00/18] threaded/atomic console support John Ogness
2023-03-02 19:56 ` [PATCH printk v1 05/18] printk: Add non-BKL console basic infrastructure John Ogness
2023-03-09 14:08   ` global states: was: " Petr Mladek
2023-03-17 13:29     ` John Ogness
2023-03-09 15:32   ` naming: " Petr Mladek
2023-03-17 13:39     ` John Ogness
2023-03-21 16:04   ` union: was: " Petr Mladek
2023-03-27 16:28     ` John Ogness
2023-03-28  8:20       ` Petr Mladek
2023-03-28  9:42         ` John Ogness
2023-03-28 12:52           ` Petr Mladek [this message]
2023-03-28 13:47           ` Steven Rostedt
2023-03-02 19:58 ` [PATCH printk v1 00/18] serial: 8250: implement non-BKL console John Ogness
2023-03-28 13:33   ` locking API: was: " Petr Mladek
2023-03-28 13:57     ` John Ogness
2023-03-28 15:10       ` Petr Mladek
2023-03-28 21:47         ` John Ogness
2023-03-29  8:03           ` Petr Mladek
2023-03-28 13:59   ` [PATCH printk v1 00/18] POC: serial: 8250: implement nbcon console John Ogness
2023-03-09 10:55 ` [PATCH printk v1 00/18] threaded/atomic console support Daniel Thompson
2023-03-09 11:14   ` John Ogness

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