When I implemented virtio's hash-related features to tun/tap [1],
I found tun/tap does not fill the entire region reserved for the virtio
header, leaving some uninitialized hole in the middle of the buffer
after read()/recvmesg().

This series fills the uninitialized hole. More concretely, the
num_buffers field will be initialized with 1, and the other fields will
be inialized with 0. Setting the num_buffers field to 1 is mandated by
virtio 1.0 [2].

The change to virtio header is preceded by another change that refactors
tun and tap to unify their virtio-related code.

[1]: https://lore.kernel.org/r/20241008-rss-v5-0-f3cf68df005d@daynix.com (local)
[2]: https://lore.kernel.org/r/20241227084256-mutt-send-email-mst@kernel.org/ (local)

Signed-off-by: Akihiko Odaki <redacted>
---
Changes in v2:
- Fixed num_buffers endian.
- Link to v1: https://lore.kernel.org/r/20250108-tun-v1-0-67d784b34374@daynix.com (local)

---
Akihiko Odaki (3):
      tun: Unify vnet implementation
      tun: Pad virtio header with zero
      tun: Set num_buffers for virtio 1.0

 MAINTAINERS            |   1 +
 drivers/net/Kconfig    |   5 ++
 drivers/net/Makefile   |   1 +
 drivers/net/tap.c      | 174 ++++++----------------------------------
 drivers/net/tun.c      | 214 +++++++++----------------------------------------
 drivers/net/tun_vnet.c | 191 +++++++++++++++++++++++++++++++++++++++++++
 drivers/net/tun_vnet.h |  24 ++++++
 7 files changed, 283 insertions(+), 327 deletions(-)
---
base-commit: a32e14f8aef69b42826cf0998b068a43d486a9e9
change-id: 20241230-tun-66e10a49b0c7

Best regards,
-- 
Akihiko Odaki [off-list ref]