Re: [PATCH 0/3] vmsplice: make vmsplice a trivial wrapper for preadv2/pwritev2

[Askar Safin <safinaskar@gmail.com>]

Linus Torvalds <torvalds@linux-foundation.org>:
> That isn't what Askar's patch ever did.
> 
> You apparently didn't even read it.
> 
> Honestly, I think you are the one out of line here.
> 
> Askar did something I suggested years ago, and didn't remove any functionality.
> 
> It just changes vmsplice to be a copying model (one of the directions
> already was). It doesn't change regular splice at all.

Pedro is talking here not about this vmsplice patch, but about
my future hypothetical patch, which will remove splice-pagecache-to-pipe.

Let me clarify, what I want to send: I will make splice-pagecache-to-pipe
be a copy. I. e. this splice direction will continue to work, but will be
possibly slower. I. e. I will do something like this (see end of this email)
(absolutely not tested), and the same thing for other filesystems,
and also I will remove resulting dead code and remove
pipe_buf_operations::confirm (it will likely become unneeded).

If Pedro sends this instead, this will be okay.

diff --git i/fs/ext2/file.c w/fs/ext2/file.c
index d9b1eb34694a..8edcc3769793 100644
--- i/fs/ext2/file.c
+++ w/fs/ext2/file.c
@@ -326,7 +326,7 @@ const struct file_operations ext2_file_operations = {
        .release        = ext2_release_file,
        .fsync          = ext2_fsync,
        .get_unmapped_area = thp_get_unmapped_area,
-       .splice_read    = filemap_splice_read,
+       .splice_read    = copy_splice_read,
        .splice_write   = iter_file_splice_write,
        .setlease       = generic_setlease,
 };

-- 
Askar Safin