[PATCH net v2 0/2] vsock/virtio: fix msg_iter desync on transmission failure

[Octavian Purdila <tavip@google.com>]

This series fixes a msg_iter desync issue in the virtio vsock transport
that can lead to warnings and eventual -ENOMEM under specific failure
scenarios (e.g. partial GUP failure during MSG_ZEROCOPY transmission).

To fix this, we need to restore the msg_iter state on transmission failure.
However, since virtio vsock transport can be built as a module, we first
need to export iov_iter_restore.

Patch 1 exports iov_iter_restore.
Patch 2 implements the msg_iter restoration in virtio vsock.

Changes in v2:
- Use iov_iter_savestate()/iov_iter_restore() (Stefano)
- Use a single restore point (Stefano)
- Reverse xmas tree (Stefano)
- Added comments in the code (Stefano)

v1: https://lore.kernel.org/all/20260609004809.1285028-1-tavip@google.com/

Octavian Purdila (2):
  iov_iter: export iov_iter_restore
  vsock/virtio: restore msg_iter on transmission failure

 lib/iov_iter.c                          |  1 +
 net/vmw_vsock/virtio_transport_common.c | 13 +++++++++++++
 2 files changed, 14 insertions(+)

-- 
2.54.0.1136.gdb2ca164c4-goog