svcrdma: Add support to svc_rdma_send to handle chained WR

WR can be submitted as linked lists of WR. Update the svc_rdma_send
routine to handle WR chains. This will be used to submit a WR that
uses an FRMR with another WR that invalidates the FRMR.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index d9183cb..f22f587 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -1235,17 +1235,23 @@ int svc_rdma_fastreg(struct svcxprt_rdma *xprt,
 
 int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
 {
-       struct ib_send_wr *bad_wr;
+       struct ib_send_wr *bad_wr, *n_wr;
+       int wr_count;
+       int i;
        int ret;
 
        if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
                return -ENOTCONN;
 
        BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
+       wr_count = 1;
+       for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
+               wr_count++;
+
        /* If the SQ is full, wait until an SQ entry is available */
        while (1) {
                spin_lock_bh(&xprt->sc_lock);
-               if (xprt->sc_sq_depth == atomic_read(&xprt->sc_sq_count)) {
+               if (xprt->sc_sq_depth < atomic_read(&xprt->sc_sq_count) + wr_count) {
                        spin_unlock_bh(&xprt->sc_lock);
                        atomic_inc(&rdma_stat_sq_starve);
 
@@ -1260,19 +1266,26 @@ int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
                                return 0;
                        continue;
                }
-               /* Bumped used SQ WR count and post */
-               svc_xprt_get(&xprt->sc_xprt);
+               /* Take a transport ref for each WR posted */
+               for (i = 0; i < wr_count; i++)
+                       svc_xprt_get(&xprt->sc_xprt);
+
+               /* Bump used SQ WR count and post */
+               atomic_add(wr_count, &xprt->sc_sq_count);
                ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
-               if (!ret)
-                       atomic_inc(&xprt->sc_sq_count);
-               else {
-                       svc_xprt_put(&xprt->sc_xprt);
+               if (ret) {
+                       set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
+                       atomic_sub(wr_count, &xprt->sc_sq_count);
+                       for (i = 0; i < wr_count; i ++)
+                               svc_xprt_put(&xprt->sc_xprt);
                        dprintk("svcrdma: failed to post SQ WR rc=%d, "
                               "sc_sq_count=%d, sc_sq_depth=%d\n",
                               ret, atomic_read(&xprt->sc_sq_count),
                               xprt->sc_sq_depth);
                }
                spin_unlock_bh(&xprt->sc_lock);
+               if (ret)
+                       wake_up(&xprt->sc_send_wait);
                break;
        }
        return ret;