xprtrdma: Handle stale connection rejection

A server rejects a connection attempt with STALE_CONNECTION when a
client attempts to connect to a working remote service, but uses a
QPN and GUID that corresponds to an old connection that was
abandoned. This might occur after a client crashes and restarts.

Fix rpcrdma_conn_upcall() to distinguish between a normal rejection
and rejection of stale connection parameters.

As an additional clean-up, remove the code that retries the
connection attempt with different ORD/IRD values. Code audit of
other ULP initiators shows no similar special case handling of
initiator_depth or responder_resources.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 21 insertions, 45 deletions

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 61d16c39e92c..d1ee33fa8055 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -54,6 +54,7 @@
 #include <linux/sunrpc/svc_rdma.h>
 #include <asm/bitops.h>
 #include <linux/module.h> /* try_module_get()/module_put() */
+#include <rdma/ib_cm.h>
 
 #include "xprt_rdma.h"
 
@@ -279,7 +280,14 @@ rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
                 connstate = -ENETDOWN;
                 goto connected;
         case RDMA_CM_EVENT_REJECTED:
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+                pr_info("rpcrdma: connection to %pIS:%u on %s rejected: %s\n",
+                        sap, rpc_get_port(sap), ia->ri_device->name,
+                        rdma_reject_msg(id, event->status));
+#endif
                 connstate = -ECONNREFUSED;
+                if (event->status == IB_CM_REJ_STALE_CONN)
+                        connstate = -EAGAIN;
                 goto connected;
         case RDMA_CM_EVENT_DISCONNECTED:
                 connstate = -ECONNABORTED;
@@ -643,20 +651,21 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 int
 rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 {
+        struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt,
+                                                   rx_ia);
         struct rdma_cm_id *id, *old;
+        struct sockaddr *sap;
+        unsigned int extras;
         int rc = 0;
-        int retry_count = 0;
 
         if (ep->rep_connected != 0) {
-                struct rpcrdma_xprt *xprt;
 retry:
                 dprintk("RPC:       %s: reconnecting...\n", __func__);
 
                 rpcrdma_ep_disconnect(ep, ia);
 
-                xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
-                id = rpcrdma_create_id(xprt, ia,
-                                (struct sockaddr *)&xprt->rx_data.addr);
+                sap = (struct sockaddr *)&r_xprt->rx_data.addr;
+                id = rpcrdma_create_id(r_xprt, ia, sap);
                 if (IS_ERR(id)) {
                         rc = -EHOSTUNREACH;
                         goto out;
@@ -711,51 +720,18 @@ retry:
         }
 
         wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0);
-
-        /*
-         * Check state. A non-peer reject indicates no listener
-         * (ECONNREFUSED), which may be a transient state. All
-         * others indicate a transport condition which has already
-         * undergone a best-effort.
-         */
-        if (ep->rep_connected == -ECONNREFUSED &&
-            ++retry_count <= RDMA_CONNECT_RETRY_MAX) {
-                dprintk("RPC:       %s: non-peer_reject, retry\n", __func__);
-                goto retry;
-        }
         if (ep->rep_connected <= 0) {
-                /* Sometimes, the only way to reliably connect to remote
-                 * CMs is to use same nonzero values for ORD and IRD. */
-                if (retry_count++ <= RDMA_CONNECT_RETRY_MAX + 1 &&
-                    (ep->rep_remote_cma.responder_resources == 0 ||
-                     ep->rep_remote_cma.initiator_depth !=
-                                ep->rep_remote_cma.responder_resources)) {
-                        if (ep->rep_remote_cma.responder_resources == 0)
-                                ep->rep_remote_cma.responder_resources = 1;
-                        ep->rep_remote_cma.initiator_depth =
-                                ep->rep_remote_cma.responder_resources;
+                if (ep->rep_connected == -EAGAIN)
                         goto retry;
-                }
                 rc = ep->rep_connected;
-        } else {
-                struct rpcrdma_xprt *r_xprt;
-                unsigned int extras;
-
-                dprintk("RPC:       %s: connected\n", __func__);
-
-                r_xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
-                extras = r_xprt->rx_buf.rb_bc_srv_max_requests;
-
-                if (extras) {
-                        rc = rpcrdma_ep_post_extra_recv(r_xprt, extras);
-                        if (rc) {
-                                pr_warn("%s: rpcrdma_ep_post_extra_recv: %i\n",
-                                        __func__, rc);
-                                rc = 0;
-                        }
-                }
+                goto out;
         }
 
+        dprintk("RPC:       %s: connected\n", __func__);
+        extras = r_xprt->rx_buf.rb_bc_srv_max_requests;
+        if (extras)
+                rpcrdma_ep_post_extra_recv(r_xprt, extras);
+
 out:
         if (rc)
                 ep->rep_connected = rc;