The first patch avoid spuriously returning 1 [*] when zero-copy flush is
attempted before any buffer was sent using MSG_ZEROCOPY.

[*] zero-copy not being used, even though it's enabled and supported
by kernel

The second patch introduces a new migration stat (zero-copy-copied)
that will be used to keep track of [*]. 

Honestly I would like some help with this naming, which I don't think
is quite good, but I could also not think on anything better.

The third patch keeps track of how many zero-copy flushes retured 1 [*]

Leonardo Bras (3):
  QIOChannelSocket: Fix zero-copy flush returning code 1 when nothing
    sent
  Add zero-copy-copied migration stat
  migration/multifd: Warn user when zerocopy not working

 qapi/migration.json   | 5 ++++-
 migration/ram.h       | 2 ++
 io/channel-socket.c   | 8 +++++++-
 migration/migration.c | 1 +
 migration/multifd.c   | 2 ++
 migration/ram.c       | 5 +++++
 monitor/hmp-cmds.c    | 4 ++++
 7 files changed, 25 insertions(+), 2 deletions(-)

-- 
2.36.1