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>

1 files changed, 21 insertions, 8 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index d9183cbcd967..f22f58767661 100644
--- 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;