svcrdma: Reduce max_send_sges

There's no need to request a large number of send SGEs because the
inline threshold already constrains the number of SGEs per Send.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 2848cafd4a17..2f7ec8912f49 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -475,10 +475,12 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 
         /* Qualify the transport resource defaults with the
          * capabilities of this particular device */
-        newxprt->sc_max_send_sges = dev->attrs.max_send_sge;
-        /* transport hdr, head iovec, one page list entry, tail iovec */
-        if (newxprt->sc_max_send_sges < 4) {
-                pr_err("svcrdma: too few Send SGEs available (%d)\n",
+        /* Transport header, head iovec, tail iovec */
+        newxprt->sc_max_send_sges = 3;
+        /* Add one SGE per page list entry */
+        newxprt->sc_max_send_sges += svcrdma_max_req_size / PAGE_SIZE;
+        if (newxprt->sc_max_send_sges > dev->attrs.max_send_sge) {
+                pr_err("svcrdma: too few Send SGEs available (%d needed)\n",
                        newxprt->sc_max_send_sges);
                 goto errout;
         }