Subject: Re: [PATCH 0/6] kernel tinification: optionally compile out splice family of syscalls (splice, vmsplice, tee and sendfile)

From: Josh Triplett <[email-masked]>
Date: Sun, 23 Nov 2014 11:43:26 -0800

On Sun, Nov 23, 2014 at 01:46:23PM -0500, David Miller wrote:
> Truly removing sendfile/sendpage means that you can't even compile NFS
> into the tree.

If you mean the in-kernel nfsd (CONFIG_NFSD), that already has a large
stack of "select" and "depends on", both directly and indirectly; adding
a "select SPLICE_SYSCALL" to it seems fine.  (That select does need
adding, though.  Pieter, you need to test-compile more than just
tinyconfig and defconfig.  Try an allyesconfig with *just* splice turned
off, and make sure that compiles.)

Given the requirements of running a file server in the kernel, I'd
expect CONFIG_NFSD to end up with several more selects of optional
functionality in the future.  It seems rather likely that the average
embedded system will be compiling out NFS. :)

Also, this patch series compiles out splice and sendfile, including
several *users* of sendpage; it doesn't compile out the sendpage
support/infrastructure itself.

- Josh Triplett