Change vsock's lingerning to wait, on close() and shutdown(), until all
data is sent, i.e. until workers picked all the packets for processing.

Changes in v1:
- Do not assume `unsent_bytes()` is implemented by all transports [Stefano]
- Link to v0: https://lore.kernel.org/netdev/df2d51fd-03e7-477f-8aea-938446f47864@rbox.co/

Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
Michal Luczaj (2):
      vsock: Linger on unsent data
      vsock/test: Expand linger test to ensure close() does not misbehave

 include/net/af_vsock.h                  |  1 +
 net/vmw_vsock/af_vsock.c                | 25 +++++++++++++++++++++++++
 net/vmw_vsock/virtio_transport_common.c | 25 +++----------------------
 tools/testing/vsock/vsock_test.c        | 30 +++++++++++++++++++++++++++---
 4 files changed, 56 insertions(+), 25 deletions(-)
---
base-commit: 61f96e684edd28ca40555ec49ea1555df31ba619
change-id: 20250304-vsock-linger-9026e5f9986c

Best regards,
-- 
Michal Luczaj <mhal@rbox.co>