On 2024/10/09 22:55, Willem de Bruijn wrote:
Akihiko Odaki wrote:
Both tun and tap exposes the same set of virtio-net-related features.
Unify their implementations to ease future changes.
Signed-off-by: Akihiko Odaki <akihiko.odaki@xxxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/net/tap.c | 172 ++++++----------------------------------
drivers/net/tun.c | 208 ++++++++-----------------------------------------
drivers/net/tun_vnet.h | 181 ++++++++++++++++++++++++++++++++++++++++++
Same point: should not be in a header.
Also: I've looked into deduplicating code between the various tun, tap
and packet socket code as well.
In general it's a good idea. The main counter arguments is that such a
break in continuity also breaks backporting fixes to stable. So the
benefit must outweight that cost.
In this case, the benefits in terms of LoC are rather modest. Not sure
it's worth it.
Even more importantly: are the two code paths that you deduplicate
exactly identical? Often in the past the two subtly diverged over
time, e.g., due to new features added only to one of the two.
I find extracting the virtio_net-related code into functions is
beneficial. For example, tun_get_user() is a big function and extracting
the virtio_net-related code into tun_vnet_hdr_get() will ease
understanding tun_get_user() when you are not interested in virtio_net.
If virtio_net is your interest, you can look at this group of functions
to figure out how they interact with each other.
Currently, the extracted code is almost identical for tun and tap so
they can share it. We can copy the code back (but keep functions as
semantic units) if they diverge in the future.
If so, call out any behavioral changes to either as a result of
deduplicating explicitly.
This adds an error message for GSO failure, which was missing for tap. I
will note that in the next version.
