Re: [PATCH] udp: Rename udp_buf_sock_to_tap() and udp_vu_sock_to_tap()

[David Gibson <david@gibson.dropbear.id.au>]

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On Sat, Dec 13, 2025 at 02:55:08AM +0100, Stefano Brivio wrote:
> On Fri, 12 Dec 2025 13:30:32 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > On Thu, Dec 11, 2025 at 03:16:26PM +0100, Laurent Vivier wrote:
> > > The function udp_vu_sock_to_tap() sends data to the vhost-user interface,
> > > not the tap interface. Rename it to udp_sock_to_vu() to accurately reflect
> > > its destination.
> > > 
> > > The function udp_buf_sock_to_tap() includes a "buf_" prefix that is now
> > > redundant. Since the functions can be distinguished by their destination
> > > (to_tap vs. to_vu), drop the prefix and rename it to udp_sock_to_tap().
> > > 
> > > No functional change.
> > > 
> > > Signed-off-by: Laurent Vivier <lvivier@redhat.com>  
> > 
> > Eh, I mean using "tap" to mean the guest side interface, even if it's
> > not based on /dev/net/tap is pretty well established at this point.
> > 
> > I do think udp_sock_to_vu() is a better name regardless.  I'm a bit
> > less convinced on renaming udp_buf_sock_to_tap().  If we're trying to
> > abandon the "tap means any guest interface" convention, then
> > udp_sock_to_tap() is still inaccurate, since it can also send to a
> > qemu socket.  If we're not trying to abandon that convention then it
> > suggests that the function does any forwarding to the guest, not just
> > the non-vu case.
> 
> Assuming we're not trying to abandon that convention: why can't "tap"
> be "anything that's not vhost-user"? We could document that at the top
> of tap.c and it would still be clearer than the current situation.

I mean, I guess we could.  It seems weirdly arbitrary to me.

> It would be still somewhat confusing that a big part of the code in
> tap.c is also relevant for vhost-user, but in a number of places,
> there, we call the vhost-user specific implementation and return early.

Right.  We could potentially rename many of the current "tap" things
to, say "guestif"?  Although I guess that doesn't make the distinction
from the splice interface clear.

> I got to dislike "buf" over timing because it's more typing and doesn't
> mean much other than "non-vhost-user" (vhost-user uses buffers too).
> Maybe we could live happier by letting "tap" be that magic word?

I don't love it, but I don't dislike it enough to complain (much) if
you choose to go that way.

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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