From: Dan Smith <danms@us.ibm.com>
This patch adds basic checkpoint/restart support for AF_UNIX sockets. It
has been tested with a single and multiple processes, and with data inflight
at the time of checkpoint. It supports socketpair()s, path-based, and
abstract sockets.
Changes in ckpt-v21:
- Do not include checkpoint_hdr.h explicitly
- [Dan Smith] Disable softirqs when taking the socket queue lock
Changes in ckpt-v19:
- [Serge Hallyn] skb->tail can be offset
Changes in ckpt-v19-rc3:
- Rebase to kernel 2.6.33: export and leverage sock_alloc_file()
- [Nathan Lynch] Fix net/checkpoint.c for 64-bit
Changes in ckpt-v19-rc2:
- Change select uses of ckpt_debug() to ckpt_err() in net c/r
- [Dan Smith] Unify skb read/write functions and handle fragmented buffers
- [Dan Smith] Update buffer restore code to match the new format
Changes in ckpt-v19-rc1:
- [Dan Smith] Fix compile issue with CONFIG_CHECKPOINT=n
- [Dan Smith] Remove an unnecessary check on socket restart
- [Matt Helsley] Add cpp definitions for enums
- [Dan Smith] Pass the stored sock->protocol into sock_create() on restore
Changes in v12:
- Collect sockets for leak-detection
- Adjust socket reference count during leak detection phase
Changes in v11:
- Create a struct socket for orphan socket during checkpoint
- Make sockets proper objhash objects and use checkpoint_obj() on them
- Rename headerless struct ckpt_hdr_* to struct ckpt_*
- Remove struct timeval from socket header
- Save and restore UNIX socket peer credentials
- Set socket flags on restore using sock_setsockopt() where possible
- Fail on the TIMESTAMPING_* flags for the moment (with a TODO)
- Remove other explicit flag checks that are no longer copied blindly
- Changed functions/variables names to follow existing conventions
- Use proto_ops->{checkpoint,restart} methods for af_unix
- Cleanup sock_file_restore()/sock_file_checkpoint()
- Make ckpt_hdr_socket be part of ckpt_hdr_file_socket
- Fold ...
