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>

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 61d16c39e92c53935c4d2f02529f83b5b86061ee..d1ee33fa8055f8fe3a659874e4e654a0d1a94518 100644 (file)
--- 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;