[PATCH net-next 0/7] RDS zerocopy support

[Sowmini Varadhan <sowmini.varadhan@oracle.com>]

This patch series follows up on the RFC and subsequent review comments
at https://patchwork.ozlabs.org/cover/862248/

Review comments addressed are
- drop MSG_PEEK change for sk_error_queue
- (patch4) batch of SO_EE_ORIGIN_MAX_ZCOOKIES (#defined to 8) is sent up
  as part of the data in the error notification. The ancillary data in
  with this notification specifies the number of cookies in ee_data,
  with the ee_origin is set to SO_EE_ORIGIN_ZCOOKIE
- (patch4, patch5) allocate the skb to be used for error notification
  up-front (in rds_sendmsg()) so that we never have to fail due to skb
  allocation failure in the callback routine.
- other minor review fixes around refactoring code for the setsockopt
  of ZEROCOPY, use iov_iter_npages()  etc.

This patch series also updates the selftests/net/msg_zerocopy.c to support
PF_RDS sockets (both with and without zerocopy)

Thanks to Willem de Bruijn and Eric Dumazet for review comments.

Sowmini Varadhan (7):
  skbuff: export mm_[un]account_pinned_pages for other modules
  rds: hold a sock ref from rds_message to the rds_sock
  sock: permit SO_ZEROCOPY on PF_RDS socket
  rds: support for zcopy completion notification
  rds: zerocopy Tx support.
  selftests/net: add support for PF_RDS sockets
  selftests/net: add zerocopy support for PF_RDS test case

 include/linux/skbuff.h                     |    3 +
 include/uapi/linux/errqueue.h              |    2 +
 include/uapi/linux/rds.h                   |    1 +
 net/core/skbuff.c                          |    6 +-
 net/core/sock.c                            |   25 ++--
 net/rds/af_rds.c                           |    7 +
 net/rds/message.c                          |  148 ++++++++++++++++++++++-
 net/rds/rds.h                              |   23 ++++-
 net/rds/recv.c                             |    2 +
 net/rds/send.c                             |   51 ++++++--
 tools/testing/selftests/net/msg_zerocopy.c |  182 +++++++++++++++++++++++-----
 11 files changed, 390 insertions(+), 60 deletions(-)