1 files changed, 95 insertions, 55 deletions

diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index d83bffa92dfc..ecdc3ad7dbb6 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -477,6 +477,86 @@ xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
 	}
 }
 
+/* Allocate a fixed-size buffer in which to construct and send the
+ * RPC-over-RDMA header for this request.
+ */
+static bool
+rpcrdma_get_rdmabuf(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
+		    gfp_t flags)
+{
+	size_t size = r_xprt->rx_data.inline_wsize;
+	struct rpcrdma_regbuf *rb;
+
+	if (req->rl_rdmabuf)
+		return true;
+
+	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, size, flags);
+	if (IS_ERR(rb))
+		return false;
+
+	r_xprt->rx_stats.hardway_register_count += size;
+	req->rl_rdmabuf = rb;
+	return true;
+}
+
+/* RPC/RDMA marshaling may choose to send payload bearing ops inline,
+ * if the resulting Call message is smaller than the inline threshold.
+ * The value of the "rq_callsize" argument accounts for RPC header
+ * requirements, but not for the data payload in these cases.
+ *
+ * See rpcrdma_inline_pullup.
+ */
+static bool
+rpcrdma_get_sendbuf(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
+		    size_t size, gfp_t flags)
+{
+	struct rpcrdma_regbuf *rb;
+	size_t min_size;
+
+	if (req->rl_sendbuf && rdmab_length(req->rl_sendbuf) >= size)
+		return true;
+
+	min_size = max_t(size_t, size, r_xprt->rx_data.inline_wsize);
+	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, min_size, flags);
+	if (IS_ERR(rb))
+		return false;
+
+	rpcrdma_free_regbuf(&r_xprt->rx_ia, req->rl_sendbuf);
+	r_xprt->rx_stats.hardway_register_count += min_size;
+	req->rl_sendbuf = rb;
+	return true;
+}
+
+/* The rq_rcv_buf is used only if a Reply chunk is necessary.
+ * The decision to use a Reply chunk is made later in
+ * rpcrdma_marshal_req. This buffer is registered at that time.
+ *
+ * Otherwise, the associated RPC Reply arrives in a separate
+ * Receive buffer, arbitrarily chosen by the HCA. The buffer
+ * allocated here for the RPC Reply is not utilized in that
+ * case. See rpcrdma_inline_fixup.
+ *
+ * A regbuf is used here to remember the buffer size.
+ */
+static bool
+rpcrdma_get_recvbuf(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
+		    size_t size, gfp_t flags)
+{
+	struct rpcrdma_regbuf *rb;
+
+	if (req->rl_recvbuf && rdmab_length(req->rl_recvbuf) >= size)
+		return true;
+
+	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, size, flags);
+	if (IS_ERR(rb))
+		return false;
+
+	rpcrdma_free_regbuf(&r_xprt->rx_ia, req->rl_recvbuf);
+	r_xprt->rx_stats.hardway_register_count += size;
+	req->rl_recvbuf = rb;
+	return true;
+}
+
 /**
  * xprt_rdma_allocate - allocate transport resources for an RPC
  * @task: RPC task
@@ -487,22 +567,18 @@ xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
  *      EIO:	A permanent error occurred, do not retry
  *
  * The RDMA allocate/free functions need the task structure as a place
- * to hide the struct rpcrdma_req, which is necessary for the actual send/recv
- * sequence.
+ * to hide the struct rpcrdma_req, which is necessary for the actual
+ * send/recv sequence.
  *
- * The RPC layer allocates both send and receive buffers in the same call
- * (rq_send_buf and rq_rcv_buf are both part of a single contiguous buffer).
- * We may register rq_rcv_buf when using reply chunks.
+ * xprt_rdma_allocate provides buffers that are already mapped for
+ * DMA, and a local DMA lkey is provided for each.
  */
 static int
 xprt_rdma_allocate(struct rpc_task *task)
 {
 	struct rpc_rqst *rqst = task->tk_rqstp;
-	size_t size = rqst->rq_callsize + rqst->rq_rcvsize;
 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
-	struct rpcrdma_regbuf *rb;
 	struct rpcrdma_req *req;
-	size_t min_size;
 	gfp_t flags;
 
 	req = rpcrdma_buffer_get(&r_xprt->rx_buf);
@@ -513,59 +589,23 @@ xprt_rdma_allocate(struct rpc_task *task)
 	if (RPC_IS_SWAPPER(task))
 		flags = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
 
-	if (req->rl_rdmabuf == NULL)
-		goto out_rdmabuf;
-	if (req->rl_sendbuf == NULL)
-		goto out_sendbuf;
-	if (size > req->rl_sendbuf->rg_size)
-		goto out_sendbuf;
+	if (!rpcrdma_get_rdmabuf(r_xprt, req, flags))
+		goto out_fail;
+	if (!rpcrdma_get_sendbuf(r_xprt, req, rqst->rq_callsize, flags))
+		goto out_fail;
+	if (!rpcrdma_get_recvbuf(r_xprt, req, rqst->rq_rcvsize, flags))
+		goto out_fail;
+
+	dprintk("RPC: %5u %s: send size = %zd, recv size = %zd, req = %p\n",
+		task->tk_pid, __func__, rqst->rq_callsize,
+		rqst->rq_rcvsize, req);
 
-out:
-	dprintk("RPC:       %s: size %zd, request 0x%p\n", __func__, size, req);
 	req->rl_connect_cookie = 0;	/* our reserved value */
 	rpcrdma_set_xprtdata(rqst, req);
 	rqst->rq_buffer = req->rl_sendbuf->rg_base;
-	rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_rcvsize;
+	rqst->rq_rbuffer = req->rl_recvbuf->rg_base;
 	return 0;
 
-out_rdmabuf:
-	min_size = r_xprt->rx_data.inline_wsize;
-	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, min_size, flags);
-	if (IS_ERR(rb))
-		goto out_fail;
-	req->rl_rdmabuf = rb;
-
-out_sendbuf:
-	/* XDR encoding and RPC/RDMA marshaling of this request has not
-	 * yet occurred. Thus a lower bound is needed to prevent buffer
-	 * overrun during marshaling.
-	 *
-	 * RPC/RDMA marshaling may choose to send payload bearing ops
-	 * inline, if the result is smaller than the inline threshold.
-	 * The value of the "size" argument accounts for header
-	 * requirements but not for the payload in these cases.
-	 *
-	 * Likewise, allocate enough space to receive a reply up to the
-	 * size of the inline threshold.
-	 *
-	 * It's unlikely that both the send header and the received
-	 * reply will be large, but slush is provided here to allow
-	 * flexibility when marshaling.
-	 */
-	min_size = r_xprt->rx_data.inline_rsize;
-	min_size += r_xprt->rx_data.inline_wsize;
-	if (size < min_size)
-		size = min_size;
-
-	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, size, flags);
-	if (IS_ERR(rb))
-		goto out_fail;
-
-	r_xprt->rx_stats.hardway_register_count += size;
-	rpcrdma_free_regbuf(&r_xprt->rx_ia, req->rl_sendbuf);
-	req->rl_sendbuf = rb;
-	goto out;
-
 out_fail:
 	rpcrdma_buffer_put(req);
 	return -ENOMEM;