svcrdma: Fix retry loop in svc_rdma_send()

Don't call ib_post_send() at all if the transport is already
shutting down.

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

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index b6fc9299b472d6cc6c15658835c008b465edbee7..0ee9185f5f3f4a0d1a4e3512fdd2bca49db9b810 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -320,8 +320,9 @@ flushed:
  * that these values remain available after the ib_post_send() call.
  * In some error flow cases, svc_rdma_wc_send() releases @ctxt.
  *
- * Returns zero if the Send WR was posted successfully. Otherwise, a
- * negative errno is returned.
+ * Return values:
+ *   %0: @ctxt's WR chain was posted successfully
+ *   %-ENOTCONN: The connection was lost
  */
 int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt)
 {
@@ -338,30 +339,35 @@ int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt)
                                      DMA_TO_DEVICE);
 
        /* If the SQ is full, wait until an SQ entry is available */
-       while (1) {
+       while (!test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags)) {
                if ((atomic_dec_return(&rdma->sc_sq_avail) < 0)) {
                        svc_rdma_wake_send_waiters(rdma, 1);
+
+                       /* When the transport is torn down, assume
+                        * ib_drain_sq() will trigger enough Send
+                        * completions to wake us. The XPT_CLOSE test
+                        * above should then cause the while loop to
+                        * exit.
+                        */
                        percpu_counter_inc(&svcrdma_stat_sq_starve);
                        trace_svcrdma_sq_full(rdma, &cid);
                        wait_event(rdma->sc_send_wait,
                                   atomic_read(&rdma->sc_sq_avail) > 0);
-                       if (test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags))
-                               return -ENOTCONN;
                        trace_svcrdma_sq_retry(rdma, &cid);
                        continue;
                }
 
                trace_svcrdma_post_send(ctxt);
                ret = ib_post_send(rdma->sc_qp, wr, NULL);
-               if (ret)
+               if (ret) {
+                       trace_svcrdma_sq_post_err(rdma, &cid, ret);
+                       svc_xprt_deferred_close(&rdma->sc_xprt);
+                       svc_rdma_wake_send_waiters(rdma, 1);
                        break;
+               }
                return 0;
        }
-
-       trace_svcrdma_sq_post_err(rdma, &cid, ret);
-       svc_xprt_deferred_close(&rdma->sc_xprt);
-       svc_rdma_wake_send_waiters(rdma, 1);
-       return ret;
+       return -ENOTCONN;
 }
 
 /**