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Subject: Re: tty splice branch (was "Re: Splicing to/from a tty")
To:     Linus Torvalds <torvalds@linux-foundation.org>,
        Oliver Giles <ohw.giles@gmail.com>,
        Robert Karszniewicz <r.karszniewicz@phytec.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Christoph Hellwig <hch@lst.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Jiri Slaby <jirislaby@kernel.org>
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From:   Jiri Slaby <jirislaby@kernel.org>
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Date:   Thu, 21 Jan 2021 09:50:39 +0100
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On 21. 01. 21, 2:18, Linus Torvalds wrote:
> On Tue, Jan 19, 2021 at 8:44 PM Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>>
>> I'll come back to this tomorrow and do the line-buffered icanon case
>> too (unless pull requests pile up), and then I'll be happy with the
>> tty changes, and I think I can submit this series for real to Greg.
> 
> Greg, I don't know how you want to handle this.
> 
> I have a branch with my tty splice patches at
> 
>      git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git tty-splice
> 
> and that now includes doing that "cookie continuation" thing even for
> the N_TTY icanon modes.
> 
> It passes my local tests, and I did try a few rather odd things. And
> Oliver tested an ealier version without that final commit on his load.
> But...

Hm, I would like to review this first. I noticed the changes only 
because a new branch appeared when I grabbed your tree and the branch 
has "tty" in its name.

So for example:

> @@ -1038,18 +1045,15 @@ static ssize_t tty_write(struct file *file, const char __user *buf,
>         if (tty->ops->write_room == NULL)
>                 tty_err(tty, "missing write_room method\n");
>         ld = tty_ldisc_ref_wait(tty);
> -       if (!ld)
> -               return hung_up_tty_write(file, buf, count, ppos);
> -       if (!ld->ops->write)
> +       if (!ld || !ld->ops->write)
>                 ret = -EIO;
>         else
> -               ret = do_tty_write(ld->ops->write, tty, file, buf, count);
> +               ret = do_tty_write(ld->ops->write, tty, file, from);
>         tty_ldisc_deref(ld);

if ld == NULL => crash here.

So can you send the patches to the list and Cc me too?

>         return ret;
>  }
thanks,
-- 
js