K 10
svn:author
V 3
mav
K 8
svn:date
V 27
2019-02-23T23:35:52.476050Z
K 7
svn:log
V 460
Free some space in struct ctl_io_hdr for better use.

 - Collapse original_sc and serializing_sc fields into one, since they
are never used simultanously, we have only one local I/O and one remote.

 - Move remote_sglist and local_sglist fields into CTL_PRIV_BACKEND,
since they are used only on Originating SC in XFER mode, where requests
don't ever reach backends, so we can reuse backend's private storage.

MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.

END