[PATCH] rpcrdma: decref EP only if ESTABLISHED and handle DEVICE_REMOVAL

[Dan Aloni <dan.aloni@vastdata.com>]

Under the scenario of IB device bonding, when bringing down one of the
ports, or all ports, we saw xprtrdma entering a non-recoverable state
where it is not even possible to complete the disconnect and shut it
down the mount, requiring a reboot.

If a DEVICE_REMOVAL happened, it may be irrespective of whether the
CM_ID is connected, and ESTABLISHED may not have happened, so we need
to avoid a decref, plus make sure connect path is woken up.

Fixes: 2acc5cae2923 ('xprtrdma: Prevent dereferencing r_xprt->rx_ep after it is freed')
Signed-off-by: Dan Aloni <dan.aloni@vastdata.com>
---
 net/sunrpc/xprtrdma/verbs.c     | 9 +++++++--
 net/sunrpc/xprtrdma/xprt_rdma.h | 1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 4f8d7efa469f..43d7d6604c30 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -244,12 +244,15 @@ rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
 		pr_info("rpcrdma: removing device %s for %pISpc\n",
 			ep->re_id->device->name, sap);
-		fallthrough;
+		ep->re_connect_status = -ENODEV;
+		wake_up_all(&ep->re_connect_wait);
+		goto disconnected;
 	case RDMA_CM_EVENT_ADDR_CHANGE:
 		ep->re_connect_status = -ENODEV;
 		goto disconnected;
 	case RDMA_CM_EVENT_ESTABLISHED:
 		rpcrdma_ep_get(ep);
+		ep->re_connect_ref = true;
 		ep->re_connect_status = 1;
 		rpcrdma_update_cm_private(ep, &event->param.conn);
 		trace_xprtrdma_inline_thresh(ep);
@@ -272,7 +275,9 @@ rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 		ep->re_connect_status = -ECONNABORTED;
 disconnected:
 		rpcrdma_force_disconnect(ep);
-		return rpcrdma_ep_put(ep);
+		if (ep->re_connect_ref)
+			return rpcrdma_ep_put(ep);
+		return 0;
 	default:
 		break;
 	}
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index da409450dfc0..1553ef69a844 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -84,6 +84,7 @@ struct rpcrdma_ep {
 	unsigned int		re_max_inline_recv;
 	int			re_async_rc;
 	int			re_connect_status;
+	bool			re_connect_ref;
 	atomic_t		re_receiving;
 	atomic_t		re_force_disconnect;
 	struct ib_qp_init_attr	re_attr;
-- 
2.39.3