From: Linus Torvalds <[email protected]>
To: Jens Axboe <[email protected]>
Cc: Ming Lei <[email protected]>, Andy Lutomirski <[email protected]>,
Dave Chinner <[email protected]>,
Matthew Wilcox <[email protected]>,
Stefan Metzmacher <[email protected]>,
linux-fsdevel <[email protected]>,
Linux API Mailing List <[email protected]>,
io-uring <[email protected]>,
"[email protected]" <[email protected]>,
Al Viro <[email protected]>,
Samba Technical <[email protected]>
Subject: Re: copy on write for splice() from file to pipe?
Date: Fri, 10 Feb 2023 14:35:11 -0800 [thread overview]
Message-ID: <CAHk-=wg3gLL-f6XkQo4vw42Q+ySPrMdprNL1dxNrr3RGHzhnrw@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
On Fri, Feb 10, 2023 at 2:26 PM Jens Axboe <[email protected]> wrote:
> >
> > (I actually suspect that /dev/zero no longer works as a splice source,
> > since we disabled the whole "fall back to regular IO" that Christoph
> > did in 36e2c7421f02 "fs: don't allow splice read/write without
> > explicit ops").
>
> Yet another one... Since it has a read_iter, should be fixable with just
> adding the generic splice_read.
I actually very consciously did *not* want to add cases of
generic_splice_read() "just because we can".
I've been on a "let's minimize the reach of splice" thing for a while.
I really loved Christoph's patches, even if I may not have been hugely
vocal about it. His getting rid of set/get_fs() got rid of a *lot* of
splice pain.
And rather than try to make everything work with splice that used to
work just because it fell back on read/write, I was waiting for actual
regression reports.
Even when splice fails, a lot of user space then falls back on
read/write, and unless there is some really fundamental reason not to,
I think that's always the right thing to do.
So we do have a number of "add splice_write/splice_read" commits, but
they are hopefully all the result of people actually noticing
breakage.
You can do
git log --grep=36e2c7421f02
to see at least some of them, and I really don't want to see them
without a "Reported-by" and an actual issue.
Exactly because I'm not all that enamoured with splice any more.
Linus
next prev parent reply other threads:[~2023-02-10 22:35 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-09 13:55 copy on write for splice() from file to pipe? Stefan Metzmacher
2023-02-09 14:11 ` Matthew Wilcox
2023-02-09 14:29 ` Stefan Metzmacher
2023-02-09 16:41 ` Linus Torvalds
2023-02-09 19:17 ` Stefan Metzmacher
2023-02-09 19:36 ` Linus Torvalds
2023-02-09 19:48 ` Linus Torvalds
2023-02-09 20:33 ` Jeremy Allison
2023-02-10 20:45 ` Stefan Metzmacher
2023-02-10 20:51 ` Linus Torvalds
2023-02-10 2:16 ` Dave Chinner
2023-02-10 4:06 ` Dave Chinner
2023-02-10 4:44 ` Matthew Wilcox
2023-02-10 6:57 ` Dave Chinner
2023-02-10 15:14 ` Andy Lutomirski
2023-02-10 16:33 ` Linus Torvalds
2023-02-10 17:57 ` Andy Lutomirski
2023-02-10 18:19 ` Jeremy Allison
2023-02-10 19:29 ` Stefan Metzmacher
2023-02-10 18:37 ` Linus Torvalds
2023-02-10 19:01 ` Andy Lutomirski
2023-02-10 19:18 ` Linus Torvalds
2023-02-10 19:27 ` Jeremy Allison
2023-02-10 19:42 ` Stefan Metzmacher
2023-02-10 19:42 ` Linus Torvalds
2023-02-10 19:54 ` Stefan Metzmacher
2023-02-10 19:29 ` Linus Torvalds
2023-02-13 9:07 ` Herbert Xu
2023-02-10 19:55 ` Andy Lutomirski
2023-02-10 20:27 ` Linus Torvalds
2023-02-10 20:32 ` Jens Axboe
2023-02-10 20:36 ` Linus Torvalds
2023-02-10 20:39 ` Jens Axboe
2023-02-10 20:44 ` Linus Torvalds
2023-02-10 20:50 ` Jens Axboe
2023-02-10 21:14 ` Andy Lutomirski
2023-02-10 21:27 ` Jens Axboe
2023-02-10 21:51 ` Jens Axboe
2023-02-10 22:08 ` Linus Torvalds
2023-02-10 22:16 ` Jens Axboe
2023-02-10 22:17 ` Linus Torvalds
2023-02-10 22:25 ` Jens Axboe
2023-02-10 22:35 ` Linus Torvalds [this message]
2023-02-10 22:51 ` Jens Axboe
2023-02-11 3:18 ` Ming Lei
2023-02-11 6:17 ` Ming Lei
2023-02-11 14:13 ` Jens Axboe
2023-02-11 15:05 ` Ming Lei
2023-02-11 15:33 ` Jens Axboe
2023-02-11 18:57 ` Linus Torvalds
2023-02-12 2:46 ` Jens Axboe
2023-02-10 4:47 ` Linus Torvalds
2023-02-10 6:19 ` Dave Chinner
2023-02-10 17:23 ` Linus Torvalds
2023-02-10 17:47 ` Linus Torvalds
2023-02-13 9:28 ` Herbert Xu
2023-02-10 22:41 ` David Laight
2023-02-10 22:51 ` Jens Axboe
2023-02-13 9:30 ` Herbert Xu
2023-02-13 9:25 ` Herbert Xu
2023-02-13 18:01 ` Andy Lutomirski
2023-02-14 1:22 ` Herbert Xu
2023-02-17 23:13 ` Andy Lutomirski
2023-02-20 4:54 ` Herbert Xu
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