linux-kernel - Re: [PATCH 2/3] futex: Store time as ktime

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Message-ID: <qzqldbanacnrdwtqbgplxmgucfzijelq5mhciyykldok6pocwr@mdkezu5pinxa>
Date: Mon, 10 Nov 2025 12:09:25 +0100
From: Jan Kara <jack@...e.cz>
To: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Cc: Alexander Viro <viro@...iv.linux.org.uk>, 
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>, Thomas Gleixner <tglx@...utronix.de>, 
	Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
	Darren Hart <dvhart@...radead.org>, Davidlohr Bueso <dave@...olabs.net>, 
	André Almeida <andrealmeid@...lia.com>, Anna-Maria Behnsen <anna-maria@...utronix.de>, 
	Frederic Weisbecker <frederic@...nel.org>, linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] futex: Store time as ktime_t in restart block

On Mon 10-11-25 10:38:52, Thomas Weißschuh wrote:
> The futex core uses ktime_t to represent times,
> use that also for the restart block.
> 
> This also allows the simplification of the accessors.
> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  include/linux/restart_block.h | 2 +-
>  kernel/futex/waitwake.c       | 9 ++++-----
>  2 files changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h
> index 0798a4ae67c6c75749c38c4673ab8ea012261319..3c2bd13f609120a8a914f6e738ffea97bf72c32d 100644
> --- a/include/linux/restart_block.h
> +++ b/include/linux/restart_block.h
> @@ -33,7 +33,7 @@ struct restart_block {
>  			u32 val;
>  			u32 flags;
>  			u32 bitset;
> -			u64 time;
> +			ktime_t time;
>  			u32 __user *uaddr2;
>  		} futex;
>  		/* For nanosleep */
> diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c
> index e2bbe5509ec27a18785227358d4ff8d8f913ddc1..1c2dd03f11ec4e5d34d1a9f67ef01e05604b3bac 100644
> --- a/kernel/futex/waitwake.c
> +++ b/kernel/futex/waitwake.c
> @@ -738,12 +738,11 @@ int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, ktime_t *abs_time
>  static long futex_wait_restart(struct restart_block *restart)
>  {
>  	u32 __user *uaddr = restart->futex.uaddr;
> -	ktime_t t, *tp = NULL;
> +	ktime_t *tp = NULL;
> +
> +	if (restart->futex.flags & FLAGS_HAS_TIMEOUT)
> +		tp = &restart->futex.time;
>  
> -	if (restart->futex.flags & FLAGS_HAS_TIMEOUT) {
> -		t = restart->futex.time;
> -		tp = &t;
> -	}
>  	restart->fn = do_no_restart_syscall;
>  
>  	return (long)futex_wait(uaddr, restart->futex.flags,
> 
> -- 
> 2.51.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR