Re: [PATCH] Futex Asynchronous Interface

[Linus Torvalds <torvalds@transmeta.com>]

On Fri, 7 Jun 2002, Rusty Russell wrote:
>
> Linus, Al, is there an easier way to do this?  I stole this from sockfs,
> but I balked at another 50 lines for a proper inode creation, so I just use
> the same dentry and inode over and over.

There's nothing inherently wrong with re-using the inode and dentry -
that's what /dev/futex would do too, of course.

> It's still an awful lot of irrelevant code: what can I cut?

I don't think it's a matter of cutting, as much as possibly a matter of
tryign to share some common code. pipefs, sockfs and now this: they all do
pretty much exactly the same thing, and there is nothing that says that
they should have separate super_operations, for example, since they are
all identical.

And once you have the same super_operations, you really have the same
"fill_super" functions too. The only thing that separates these
superblocks is the root name, so that /proc gets nice output. So it should
be fine to just have

	sb = create_anon_fs("futex");

and share all of the setup code across futex/pipes/sockfs.

Which still leaves you with the

	get_unused_fd();
	get_empty_filp();
	filp->f_dentry = dget(sb->s_root);
	.. fill it ..
	fd_install(fd, filp);

but by then we're talking single lines of overhead.

		Linus