+/*
+ * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
+ * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
+ * to use the server side send routines.
+ */
+void *bc_malloc(struct rpc_task *task, size_t size)
+{
+ struct page *page;
+ struct rpc_buffer *buf;
+
+ BUG_ON(size > PAGE_SIZE - sizeof(struct rpc_buffer));
+ page = alloc_page(GFP_KERNEL);
+
+ if (!page)
+ return NULL;
+
+ buf = page_address(page);
+ buf->len = PAGE_SIZE;
+
+ return buf->data;
+}
+
+/*
+ * Free the space allocated in the bc_alloc routine
+ */
+void bc_free(void *buffer)
+{
+ struct rpc_buffer *buf;
+
+ if (!buffer)
+ return;
+
+ buf = container_of(buffer, struct rpc_buffer, data);
+ free_page((unsigned long)buf);
+}
+
+/*
+ * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
+ * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
+ */
+static int bc_sendto(struct rpc_rqst *req)
+{
+ int len;
+ struct xdr_buf *xbufp = &req->rq_snd_buf;
+ struct rpc_xprt *xprt = req->rq_xprt;
+ struct sock_xprt *transport =
+ container_of(xprt, struct sock_xprt, xprt);
+ struct socket *sock = transport->sock;
+ unsigned long headoff;
+ unsigned long tailoff;
+
+ /*
+ * Set up the rpc header and record marker stuff
+ */
+ xs_encode_tcp_record_marker(xbufp);
+
+ tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
+ headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
+ len = svc_send_common(sock, xbufp,
+ virt_to_page(xbufp->head[0].iov_base), headoff,
+ xbufp->tail[0].iov_base, tailoff);
+
+ if (len != xbufp->len) {
+ printk(KERN_NOTICE "Error sending entire callback!\n");
+ len = -EAGAIN;
+ }
+
+ return len;
+}
+
+/*
+ * The send routine. Borrows from svc_send
+ */
+static int bc_send_request(struct rpc_task *task)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+ struct svc_xprt *xprt;
+ struct svc_sock *svsk;
+ u32 len;
+
+ dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
+ /*
+ * Get the server socket associated with this callback xprt
+ */
+ xprt = req->rq_xprt->bc_xprt;
+ svsk = container_of(xprt, struct svc_sock, sk_xprt);
+
+ /*
+ * Grab the mutex to serialize data as the connection is shared
+ * with the fore channel
+ */
+ if (!mutex_trylock(&xprt->xpt_mutex)) {
+ rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
+ if (!mutex_trylock(&xprt->xpt_mutex))
+ return -EAGAIN;
+ rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
+ }
+ if (test_bit(XPT_DEAD, &xprt->xpt_flags))
+ len = -ENOTCONN;
+ else
+ len = bc_sendto(req);
+ mutex_unlock(&xprt->xpt_mutex);
+
+ if (len > 0)
+ len = 0;
+
+ return len;
+}
+
+/*
+ * The close routine. Since this is client initiated, we do nothing
+ */
+
+static void bc_close(struct rpc_xprt *xprt)
+{
+ return;
+}
+
+/*
+ * The xprt destroy routine. Again, because this connection is client
+ * initiated, we do nothing
+ */
+
+static void bc_destroy(struct rpc_xprt *xprt)
+{
+ return;
+}
+