The previous patches described as optimizations also
fixed some issues. They seem sufficient to cover all
the error cases, but the real source of the problem
lies in foreach_session() initiated by the device backend,
which can use sessions that were never seen by the
backend.
The backends are only notified when a session is
*started*, but foreach_session() iterates through
all the sessions - even those that were never started.
Vhost SCSI, for example, in the foreach_session() callbacks
used to expect svsession->svdev to be always set, but
that field is only set when the session gets started.
A perfect solution would to introduce a new backend
callback to be called on new connection. Vhost SCSI
could set e.g. svsession->svdev inside. For now we go
with much easier solution that prevents sessions from
being used in foreach-session() unless they were
started at least once. (...and e.g. got their ->svdev set)
Change-Id: Ida30a1f27f99977360d08a71a64fc92931b25b75
Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/449394
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
e051a5366e