Re: [PATCH v2 08/11] tty: splice_read: disable

[Greg Kroah-Hartman]

On Thu, Dec 21, 2023 at 04:09:10AM +0100, Ahelenia Ziemiańska wrote:
> We request non-blocking I/O in the generic copy_splice_read, but
> "the tty layer doesn't actually honor the IOCB_NOWAIT flag for
> various historical reasons.". This means that a tty->pipe splice
> will happily sleep with the pipe locked forever, and any process
> trying to take it (due to an open/read/write/&c.) will enter
> uninterruptible sleep.
> 
> This also masks inconsistent wake-ups (usually every second line)
> when splicing from ttys in icanon mode.
> 
> Link: https://lore.kernel.org/linux-fsdevel/CAHk-=wimmqG_wvSRtMiKPeGGDL816n65u=Mq2+H3-=uM2U6FmA@xxxxxxxxxxxxxx/
> Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx>
> ---

Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>