From b73c3adabdb1e2cb2f2c69bc3cbb9306aa3f9700 Mon Sep 17 00:00:00 2001 From: Ariel Nahum Date: Thu, 22 May 2014 11:00:18 +0300 Subject: [PATCH] IB/iser: Simplify connection management iSER relies on refcounting to manage iser connections establishment and teardown. Following commit 39ff05dbbbdb ("IB/iser: Enhance disconnection logic for multi-pathing"), iser connection maintain 3 references: - iscsi_endpoint (at creation stage) - cma_id (at connection request stage) - iscsi_conn (at bind stage) We can avoid taking explicit refcounts by correctly serializing iser teardown flows (graceful and non-graceful). Our approach is to trigger a scheduled work to handle ordered teardown by gracefully waiting for 2 cleanup stages to complete: 1. Cleanup of live pending tasks indicated by iscsi_conn_stop completion 2. Flush errors processing Each completed stage will notify a waiting worker thread when it is done to allow teardwon continuation. Since iSCSI connection establishment may trigger endpoint disconnect without a successful endpoint connect, we rely on the iscsi <-> iser binding (.conn_bind) to learn about the teardown policy we should take wrt cleanup stages. Since all cleanup worker threads are scheduled (release_wq) in .ep_disconnect it is safe to assume that when module_exit is called, all cleanup workers are already scheduled. Thus proper module unload shall flush all scheduled works before allowing safe exit, to guarantee no resources got left behind. Signed-off-by: Ariel Nahum Signed-off-by: Sagi Grimberg Reviewed-by: Roi Dayan Reviewed-by: Or Gerlitz Signed-off-by: Roland Dreier --- Reading git-format-patch failed