RC sessions that never reach a completion (expired, abandoned, or canceled before READY) currently vanish inside the reaper without any trace on the operational surface. Add a terminal notification callback to the C ABI so the server reports the final outcome of every session exactly once, fired from the reaper with no server lock held.
Expose rc_server_sessions_snapshot, which copies every live session
into fixed rc_session_snapshot records under the map lock and invokes
the callback once per record outside the lock. Each session records a
monotonic creation timestamp, because the prepare/ready deadlines move
as the session progresses and cannot serve as an age reference. The
state byte combines the session state machine value with a
reap-pending marker, so callers can distinguish sessions that are
about to be reaped from healthy ones. Records whose op or target does
not fit the fixed fields are skipped rather than truncated.
Wire C-side diagnostics (session reap, READY data phase outcome,
init failures) through a sink callback so the gateway can surface
them next to its own logs instead of losing them in stderr noise.
The sink is a plain C function pointer installed once after init
and valid until destroy: the Go side registers a fixed cgo
trampoline (closures cannot cross the boundary), copies the
message immediately per the lifetime contract, and never runs
under the session map lock. Error-level lines keep the existing
stderr output; --debug enables the level-2 diagnostic stream.
Wrap the v2 session core with the server-side C ABI the gateway
binds to: prepare/ready/cancel session calls, staging leases for
GET side-loading, the put-view handoff for PUT commits, session
introspection, and the server lifecycle.
The ABI owns the parts that must be shared across sessions: the
verbs device handle, global and per-principal resource limits,
session accounting with consume-once handles keyed by epoch and
nonce, the completion reference that pins a session from the
READY claim until its finalizer, and the reaper that tears
transport objects down once every reference drains. A background
thread expires sessions past their prepare or execute deadlines
so abandoned sessions cannot pin the limits, and teardown
failures keep the affected verbs objects and device alive rather
than freeing memory the NIC may still reference.
A peer-busy READY rolls the claim back and re-arms the QP
through RESET so the client can retry the same session. The
vgwrdma target now links the archive built from these sources.
Signed-off-by: Jihyeon Gim <potatogim@potatogim.net>
Jihyeon Gim
