SUNRPC: Add a bvec array to struct xdr_buf for use with iovec_iter()

Add a bvec array to struct xdr_buf, and have the client allocate it
when we need to receive data into pages.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

3 files changed, 54 insertions, 1 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 0c4b2e7d791f9..ae3b8145da35a 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1753,6 +1753,8 @@ rpc_xdr_encode(struct rpc_task *task)
 
 	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 			task->tk_msg.rpc_argp);
+	if (task->tk_status == 0)
+		xprt_request_prepare(req);
 }
 
 /*
@@ -1768,7 +1770,7 @@ call_encode(struct rpc_task *task)
 	/* Did the encode result in an error condition? */
 	if (task->tk_status != 0) {
 		/* Was the error nonfatal? */
-		if (task->tk_status == -EAGAIN)
+		if (task->tk_status == -EAGAIN || task->tk_status == -ENOMEM)
 			rpc_delay(task, HZ >> 4);
 		else
 			rpc_exit(task, task->tk_status);
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 30afbd2366566..2bbb8d38d2bf5 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -15,6 +15,7 @@
 #include <linux/errno.h>
 #include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/msg_prot.h>
+#include <linux/bvec.h>
 
 /*
  * XDR functions for basic NFS types
@@ -128,6 +129,39 @@ xdr_terminate_string(struct xdr_buf *buf, const u32 len)
 }
 EXPORT_SYMBOL_GPL(xdr_terminate_string);
 
+size_t
+xdr_buf_pagecount(struct xdr_buf *buf)
+{
+	if (!buf->page_len)
+		return 0;
+	return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+}
+
+int
+xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
+{
+	size_t i, n = xdr_buf_pagecount(buf);
+
+	if (n != 0 && buf->bvec == NULL) {
+		buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
+		if (!buf->bvec)
+			return -ENOMEM;
+		for (i = 0; i < n; i++) {
+			buf->bvec[i].bv_page = buf->pages[i];
+			buf->bvec[i].bv_len = PAGE_SIZE;
+			buf->bvec[i].bv_offset = 0;
+		}
+	}
+	return 0;
+}
+
+void
+xdr_free_bvec(struct xdr_buf *buf)
+{
+	kfree(buf->bvec);
+	buf->bvec = NULL;
+}
+
 void
 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
 		 struct page **pages, unsigned int base, unsigned int len)
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 7333874c65954..7ee9f1e996db5 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1264,6 +1264,22 @@ xprt_request_dequeue_transmit(struct rpc_task *task)
 }
 
 /**
+ * xprt_request_prepare - prepare an encoded request for transport
+ * @req: pointer to rpc_rqst
+ *
+ * Calls into the transport layer to do whatever is needed to prepare
+ * the request for transmission or receive.
+ */
+void
+xprt_request_prepare(struct rpc_rqst *req)
+{
+	struct rpc_xprt *xprt = req->rq_xprt;
+
+	if (xprt->ops->prepare_request)
+		xprt->ops->prepare_request(req);
+}
+
+/**
  * xprt_request_need_retransmit - Test if a task needs retransmission
  * @task: pointer to rpc_task
  *
@@ -1727,6 +1743,7 @@ void xprt_release(struct rpc_task *task)
 	if (req->rq_buffer)
 		xprt->ops->buf_free(task);
 	xprt_inject_disconnect(xprt);
+	xdr_free_bvec(&req->rq_rcv_buf);
 	if (req->rq_cred != NULL)
 		put_rpccred(req->rq_cred);
 	task->tk_rqstp = NULL;