xprtrdma: Allocate zero pad separately from rpcrdma_buffer

Use the new rpcrdma_alloc_regbuf() API to shrink the amount of
contiguous memory needed for a buffer pool by moving the zero
pad buffer into a regbuf.

This is for consistency with the other uses of internally
registered memory.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

3 files changed, 13 insertions, 23 deletions

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 02efcaa1bbac..7e9acd9361c5 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -549,9 +549,9 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
         if (padlen) {
                 struct rpcrdma_ep *ep = &r_xprt->rx_ep;
 
-                req->rl_send_iov[2].addr = ep->rep_pad.addr;
+                req->rl_send_iov[2].addr = rdmab_addr(ep->rep_padbuf);
                 req->rl_send_iov[2].length = padlen;
-                req->rl_send_iov[2].lkey = ep->rep_pad.lkey;
+                req->rl_send_iov[2].lkey = rdmab_lkey(ep->rep_padbuf);
 
                 req->rl_send_iov[3].addr = req->rl_send_iov[1].addr + rpclen;
                 req->rl_send_iov[3].length = rqst->rq_slen - rpclen;
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index f58521dd88e2..8a05f45d1a11 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -794,6 +794,14 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
         ep->rep_attr.qp_type = IB_QPT_RC;
         ep->rep_attr.port_num = ~0;
 
+        if (cdata->padding) {
+                ep->rep_padbuf = rpcrdma_alloc_regbuf(ia, cdata->padding,
+                                                      GFP_KERNEL);
+                if (IS_ERR(ep->rep_padbuf))
+                        return PTR_ERR(ep->rep_padbuf);
+        } else
+                ep->rep_padbuf = NULL;
+
         dprintk("RPC:       %s: requested max: dtos: send %d recv %d; "
                 "iovs: send %d recv %d\n",
                 __func__,
@@ -876,6 +884,7 @@ out2:
                 dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
                         __func__, err);
 out1:
+        rpcrdma_free_regbuf(ia, ep->rep_padbuf);
         return rc;
 }
 
@@ -902,11 +911,7 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
                 ia->ri_id->qp = NULL;
         }
 
-        /* padding - could be done in rpcrdma_buffer_destroy... */
-        if (ep->rep_pad_mr) {
-                rpcrdma_deregister_internal(ia, ep->rep_pad_mr, &ep->rep_pad);
-                ep->rep_pad_mr = NULL;
-        }
+        rpcrdma_free_regbuf(ia, ep->rep_padbuf);
 
         rpcrdma_clean_cq(ep->rep_attr.recv_cq);
         rc = ib_destroy_cq(ep->rep_attr.recv_cq);
@@ -1220,12 +1225,10 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
          *   1.  arrays for send and recv pointers
          *   2.  arrays of struct rpcrdma_req to fill in pointers
          *   3.  array of struct rpcrdma_rep for replies
-         *   4.  padding, if any
          * Send/recv buffers in req/rep need to be registered
          */
         len = buf->rb_max_requests *
                 (sizeof(struct rpcrdma_req *) + sizeof(struct rpcrdma_rep *));
-        len += cdata->padding;
 
         p = kzalloc(len, GFP_KERNEL);
         if (p == NULL) {
@@ -1241,18 +1244,6 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
         buf->rb_recv_bufs = (struct rpcrdma_rep **) p;
         p = (char *) &buf->rb_recv_bufs[buf->rb_max_requests];
 
-        /*
-         * Register the zeroed pad buffer, if any.
-         */
-        if (cdata->padding) {
-                struct rpcrdma_ep *ep = &r_xprt->rx_ep;
-                rc = rpcrdma_register_internal(ia, p, cdata->padding,
-                                            &ep->rep_pad_mr, &ep->rep_pad);
-                if (rc)
-                        goto out;
-        }
-        p += cdata->padding;
-
         INIT_LIST_HEAD(&buf->rb_mws);
         INIT_LIST_HEAD(&buf->rb_all);
         switch (ia->ri_memreg_strategy) {
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 2b69316dfd11..5630353ed240 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -88,8 +88,7 @@ struct rpcrdma_ep {
         int                     rep_connected;
         struct ib_qp_init_attr  rep_attr;
         wait_queue_head_t       rep_connect_wait;
-        struct ib_sge           rep_pad;        /* holds zeroed pad */
-        struct ib_mr            *rep_pad_mr;    /* holds zeroed pad */
+        struct rpcrdma_regbuf   *rep_padbuf;
         struct rdma_conn_param  rep_remote_cma;
         struct sockaddr_storage rep_remote_addr;
         struct delayed_work     rep_connect_worker;