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SubjectRe: [PATCH] Revert "printk: wake up all waiters"
On Thu, 26 May 2022 22:36:56 +0206
John Ogness <john.ogness@linutronix.de> wrote:

> This reverts commit 938ba4084abcf6fdd21d9078513c52f8fb9b00d0.
>
> The wait queue @log_wait never has exclusive waiters, so there
> is no need to use wake_up_interruptible_all(). Using
> wake_up_interruptible() was the correct function to wake all
> waiters.
>
> Since there are no exclusive waiters, erroneously changing
> wake_up_interruptible() to wake_up_interruptible_all() did not
> result in any behavior change. However, using
> wake_up_interruptible_all() on a wait queue without exclusive
> waiters is fundamentally wrong.
>
> Go back to using wake_up_interruptible() to wake all waiters.

(Just to show that I have been paying attention ;-)

Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

>
> Signed-off-by: John Ogness <john.ogness@linutronix.de>
> ---
> kernel/printk/printk.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index a3e1035929b0..ea3dd55709e7 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -3904,7 +3904,7 @@ static void wake_up_klogd_work_func(struct irq_work *irq_work)
> }
>
> if (pending & PRINTK_PENDING_WAKEUP)
> - wake_up_interruptible_all(&log_wait);
> + wake_up_interruptible(&log_wait);
> }
>
> static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) =

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