xprtrdma: Handle device removal outside of the CM event handler

Wait for all disconnects to complete to ensure the transport has
divested all of its hardware resources before the underlying RDMA
device can be removed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

include/trace/events/rpcrdma.h

@@ -669,6 +669,29 @@ TRACE_EVENT(xprtrdma_inline_thresh,
 DEFINE_CONN_EVENT(connect);
 DEFINE_CONN_EVENT(disconnect);
 
+TRACE_EVENT(xprtrdma_device_removal,
+	TP_PROTO(
+		const struct rdma_cm_id *id
+	),
+
+	TP_ARGS(id),
+
+	TP_STRUCT__entry(
+		__string(name, id->device->name)
+		__array(unsigned char, addr, sizeof(struct sockaddr_in6))
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		memcpy(__entry->addr, &id->route.addr.dst_addr,
+		       sizeof(struct sockaddr_in6));
+	),
+
+	TP_printk("device %s to be removed, disconnecting %pISpc\n",
+		__get_str(name), __entry->addr
+	)
+);
+
 DEFINE_RXPRT_EVENT(xprtrdma_op_inject_dsc);
 
 TRACE_EVENT(xprtrdma_op_connect,

net/sunrpc/xprtrdma/verbs.c

@@ -222,7 +222,6 @@ static void rpcrdma_update_cm_private(struct rpcrdma_ep *ep,
 static int
 rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 {
-	struct sockaddr *sap = (struct sockaddr *)&id->route.addr.dst_addr;
 	struct rpcrdma_ep *ep = id->context;
 
 	might_sleep();
@@ -241,14 +240,6 @@ rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 		ep->re_async_rc = -ENETUNREACH;
 		complete(&ep->re_done);
 		return 0;
-	case RDMA_CM_EVENT_DEVICE_REMOVAL:
-		pr_info("rpcrdma: removing device %s for %pISpc\n",
-			ep->re_id->device->name, sap);
-		switch (xchg(&ep->re_connect_status, -ENODEV)) {
-		case 0: goto wake_connect_worker;
-		case 1: goto disconnected;
-		}
-		return 0;
 	case RDMA_CM_EVENT_ADDR_CHANGE:
 		ep->re_connect_status = -ENODEV;
 		goto disconnected;
@@ -284,6 +275,14 @@ rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 	return 0;
 }
 
+static void rpcrdma_ep_removal_done(struct rpcrdma_notification *rn)
+{
+	struct rpcrdma_ep *ep = container_of(rn, struct rpcrdma_ep, re_rn);
+
+	trace_xprtrdma_device_removal(ep->re_id);
+	xprt_force_disconnect(ep->re_xprt);
+}
+
 static struct rdma_cm_id *rpcrdma_create_id(struct rpcrdma_xprt *r_xprt,
 					    struct rpcrdma_ep *ep)
 {
@@ -323,6 +322,10 @@ static struct rdma_cm_id *rpcrdma_create_id(struct rpcrdma_xprt *r_xprt,
 	if (rc)
 		goto out;
 
+	rc = rpcrdma_rn_register(id->device, &ep->re_rn, rpcrdma_ep_removal_done);
+	if (rc)
+		goto out;
+
 	return id;
 
 out:
@@ -350,6 +353,8 @@ static void rpcrdma_ep_destroy(struct kref *kref)
 		ib_dealloc_pd(ep->re_pd);
 	ep->re_pd = NULL;
 
+	rpcrdma_rn_unregister(ep->re_id->device, &ep->re_rn);
+
 	kfree(ep);
 	module_put(THIS_MODULE);
 }

net/sunrpc/xprtrdma/xprt_rdma.h

@@ -56,6 +56,7 @@
 #include <linux/sunrpc/rpc_rdma_cid.h> 	/* completion IDs */
 #include <linux/sunrpc/rpc_rdma.h> 	/* RPC/RDMA protocol */
 #include <linux/sunrpc/xprtrdma.h> 	/* xprt parameters */
+#include <linux/sunrpc/rdma_rn.h>	/* removal notifications */
 
 #define RDMA_RESOLVE_TIMEOUT	(5000)	/* 5 seconds */
 #define RDMA_CONNECT_RETRY_MAX	(2)	/* retries if no listener backlog */
@@ -92,6 +93,7 @@ struct rpcrdma_ep {
 	struct rpcrdma_connect_private
 				re_cm_private;
 	struct rdma_conn_param	re_remote_cma;
+	struct rpcrdma_notification	re_rn;
 	int			re_receive_count;
 	unsigned int		re_max_requests; /* depends on device */
 	unsigned int		re_inline_send;	/* negotiated */