linux-kernel - Re: [PATCH V2 3/9] fork: move PF_IO_WORKER's kernel frame setup to new flag

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Date:   Wed, 22 Sep 2021 14:32:37 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Mike Christie <michael.christie@...cle.com>
Cc:     hdanton@...a.com, Christoph Hellwig <hch@...radead.org>,
        Stefan Hajnoczi <stefanha@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        "Stefano Garzarella --cc virtualization @ lists . linux-foundation . org" 
        <sgarzare@...hat.com>, virtualization@...ts.linux-foundation.org,
        Christian Brauner <christian.brauner@...ntu.com>,
        Jens Axboe <axboe@...nel.dk>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 3/9] fork: move PF_IO_WORKER's kernel frame setup to
 new flag

Hi Mike,

On Tue, Sep 21, 2021 at 11:55 PM Mike Christie
<michael.christie@...cle.com> wrote:
> The vhost worker threads need the same frame setup as io_uring's worker
> threads, but handle signals differently and do not need the same
> scheduling behavior. This patch separate's the frame setup parts of
> PF_IO_WORKER into a kernel_clone_args flag, KERN_WORKER_USER.
>
> Signed-off-by: Mike Christie <michael.christie@...cle.com>

Thanks for your patch!

> --- a/arch/m68k/kernel/process.c
> +++ b/arch/m68k/kernel/process.c
> @@ -157,7 +157,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
>          */
>         p->thread.fs = get_fs().seg;
>
> -       if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
> +       if (unlikely(p->flags & (PF_KTHREAD) ||
> +                    worker_flags & KERN_WORKER_USER)) {

I guess it wouldn't hurt to add parentheses to improve
readability:

    if (unlikely((p->flags & (PF_KTHREAD)) ||
                 (worker_flags & KERN_WORKER_USER))) {

>                 /* kernel thread */
>                 memset(frame, 0, sizeof(struct fork_frame));
>                 frame->regs.sr = PS_S;

With the above fixed, for m68k:
Acked-by: Geert Uytterhoeven <geert@...ux-m68k.org>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds