linux-toradex.git/include/linux/pipe_fs_i.h, branch v2.6.27.14

pipe: add documentation and comments

2007-07-10T06:04:16+00:00

As per Andrew Mortons request, here's a set of documentation for
the generic pipe_buf_operations hooks, the pipe, and pipe_buffer
structures.

Signed-off-by: Jens Axboe

pipe: change the ->pin() operation to ->confirm()

2007-07-10T06:04:15+00:00

The name 'pin' was badly chosen, it doesn't pin a pipe buffer
in the most commonly used sense in the kernel. So change the
name to 'confirm', after debating this issue with Hugh
Dickins a bit.

A good return from ->confirm() means that the buffer is really
there, and that the contents are good.

Signed-off-by: Jens Axboe

pipe: allow passing around of ops private pointer

2007-07-10T06:04:14+00:00

relay needs this for proper consumption handling, and the network
receive support needs it as well to lookup the sk_buff on pipe
release.

Signed-off-by: Jens Axboe

splice: divorce the splice structure/function definitions from the pipe header

2007-07-10T06:04:14+00:00

We need to move even more stuff into the header so that folks can use
the splice_to_pipe() implementation instead of open-coding a lot of
pipe knowledge (see relay implementation), so move to our own header
file finally.

Signed-off-by: Jens Axboe

splice: add void cookie to the actor data

2007-07-10T06:04:14+00:00

We need that for passing driver private info.

Signed-off-by: Jens Axboe

vmsplice: add vmsplice-to-user support

2007-07-10T06:04:12+00:00

A bit of a cheat, it actually just copies the data to userspace. But
this makes the interface nice and symmetric and enables people to build
on splice, with room for future improvement in performance.

Signed-off-by: Jens Axboe

splice: abstract out actor data

2007-07-10T06:04:12+00:00

For direct splicing (or private splicing), the output may not be a file.
So abstract out the handling into a specified actor function and put
the data in the splice_desc structure earlier, so we can build on top
of that.

This is the first step in better splice handling for drivers, and also
for implementing vmsplice _to_ user memory.

Signed-off-by: Jens Axboe

pipe: move pipe_inode_info structure decleration up before it's used

2007-06-08T06:33:53+00:00

There's really no reason it's below the first use of the pointer
type, and it'll fail compilation for the network addition (for good
reason). So move it up a bit.

Signed-off-by: Jens Axboe

Export __splice_from_pipe()

2007-03-27T06:55:47+00:00

Ocfs2 wants to implement it's own splice write actor so that it can better
manage cluster / page locks. This lets us re-use the rest of splice write
while only providing our own code where it's actually important.

Signed-off-by: Mark Fasheh 
Signed-off-by: Jens Axboe

[PATCH] reorder struct pipe_buf_operations

2006-12-13T17:05:48+00:00

Fields of struct pipe_buf_operations have not a precise layout (ie not
optimized to fit cache lines nor reduce cache line ping pongs)

The bufs[] array is *large* and is placed near the beginning of the
structure, so all following fields have a large offset.  This is
unfortunate because many archs have smaller instructions when using small
offsets relative to a base register.  On x86 for example, 7 bits offsets
have smaller instruction lengths.

Moving bufs[] at the end of pipe_buf_operations permits all fields to have
small offsets, and reduce text size, and icache pressure.

# size vmlinux.pre vmlinux
    text    data     bss     dec     hex filename
3268989  664356  492196 4425541  438745 vmlinux.pre
3268765  664356  492196 4425317  438665 vmlinux

So this patch reduces text size by 224 bytes on my x86_64 machine. Similar
results on ia32.

Signed-off-by: Eric Dumazet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds