Re: Splicing to/from a tty

From: Linus Torvalds
Date: Wed Jan 20 2021 - 14:32:56 EST

On Wed, Jan 20, 2021 at 11:11 AM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> Why do we care about O_APPEND on anything without FMODE_PWRITE (including
> pipes), anyway? All writes there ignore position, after all...

We shouldn't care.

Also, I think we should try to move away from FMODE_PWRITE/PREAD
entirely, and use FMODE_STREAM as the primary "this thing doesn't have
a position at all".

That's what gets rid of all the f_pos locking etc after all. The
FMODE_PWRITE/PREAD flags are I think legacy (although we do seem to
have the seq_file case that normally allows position on reads, but not
on writes, so we may need to keep all three bits).

Anyway, I think that with FMODE_STREAM, O_APPEND definitely should be a no-op.