IB/iser: Fix DEVICE REMOVAL handling in the absence of iscsi daemon
iscsi daemon is in user-space, thus we can't rely on it to be invoked
at connection teardown (if not running or does not receive CPU time).
This patch addresses the issue by re-structuring iSER connection
teardown logic and CM events handling.
The CM events will dictate the RDMA resources destruction (ib_conn)
and iser_conn is kept around as long as iscsi_conn is left around
allowing iscsi/iser callbacks to continue after RDMA transport was
destroyed.
This patch introduces a separation in logic when handling CM events:
- DISCONNECTED_HANDLER, ADDR_CHANGED
This events indicate the start of teardown process.
Actions:
1. Terminate the connection: rdma_disconnect (send DREQ/DREP)
2. Notify iSCSI of connection failure
3. Change state to TERMINATING
4. Poll for all flush errors to be consumed
- TIMEWAIT_EXIT, DEVICE_REMOVAL
These events indicate the final stage of termination process and
we can free RDMA related resources.
Actions:
1. Call disconnected handler (we are not guaranteed that DISCONNECTED
event was invoked in the past)
2. Cleanup RDMA related resources
3. For DEVICE_REMOVAL return non-zero rc from cma_handler to
implicitly destroy the cm_id (Can't rely on user-space, make sure
we have forward progress)
We replace flush_completion (indicate all flushes were consumed) with
ib_completion (rdma resources were cleaned up).
The iser_conn_release_work will wait for teardown completions:
- conn_stop was completed (tasks were cleaned-up) - stop_completion
- RDMA resources were destroyed - ib_completion
And then will continue to free iser connection representation (iser_conn).
Signed-off-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Ariel Nahum <arieln@mellanox.com> Signed-off-by: Roi Dayan <roid@mellanox.com> Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Signed-off-by: Roland Dreier <roland@purestorage.com>