Initial import

1 files changed, 862 insertions, 0 deletions

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
new file mode 100644
index 000000000..3a57a1b0f
--- /dev/null
+++ b/fs/afs/rxrpc.c
@@ -0,0 +1,862 @@
+/* Maintain an RxRPC server socket to do AFS communications through
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include <rxrpc/packet.h>
+#include "internal.h"
+#include "afs_cm.h"
+
+static struct socket *afs_socket; /* my RxRPC socket */
+static struct workqueue_struct *afs_async_calls;
+static atomic_t afs_outstanding_calls;
+static atomic_t afs_outstanding_skbs;
+
+static void afs_wake_up_call_waiter(struct afs_call *);
+static int afs_wait_for_call_to_complete(struct afs_call *);
+static void afs_wake_up_async_call(struct afs_call *);
+static int afs_dont_wait_for_call_to_complete(struct afs_call *);
+static void afs_process_async_call(struct afs_call *);
+static void afs_rx_interceptor(struct sock *, unsigned long, struct sk_buff *);
+static int afs_deliver_cm_op_id(struct afs_call *, struct sk_buff *, bool);
+
+/* synchronous call management */
+const struct afs_wait_mode afs_sync_call = {
+	.rx_wakeup	= afs_wake_up_call_waiter,
+	.wait		= afs_wait_for_call_to_complete,
+};
+
+/* asynchronous call management */
+const struct afs_wait_mode afs_async_call = {
+	.rx_wakeup	= afs_wake_up_async_call,
+	.wait		= afs_dont_wait_for_call_to_complete,
+};
+
+/* asynchronous incoming call management */
+static const struct afs_wait_mode afs_async_incoming_call = {
+	.rx_wakeup	= afs_wake_up_async_call,
+};
+
+/* asynchronous incoming call initial processing */
+static const struct afs_call_type afs_RXCMxxxx = {
+	.name		= "CB.xxxx",
+	.deliver	= afs_deliver_cm_op_id,
+	.abort_to_error	= afs_abort_to_error,
+};
+
+static void afs_collect_incoming_call(struct work_struct *);
+
+static struct sk_buff_head afs_incoming_calls;
+static DECLARE_WORK(afs_collect_incoming_call_work, afs_collect_incoming_call);
+
+static void afs_async_workfn(struct work_struct *work)
+{
+	struct afs_call *call = container_of(work, struct afs_call, async_work);
+
+	call->async_workfn(call);
+}
+
+/*
+ * open an RxRPC socket and bind it to be a server for callback notifications
+ * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
+ */
+int afs_open_socket(void)
+{
+	struct sockaddr_rxrpc srx;
+	struct socket *socket;
+	int ret;
+
+	_enter("");
+
+	skb_queue_head_init(&afs_incoming_calls);
+
+	afs_async_calls = create_singlethread_workqueue("kafsd");
+	if (!afs_async_calls) {
+		_leave(" = -ENOMEM [wq]");
+		return -ENOMEM;
+	}
+
+	ret = sock_create_kern(AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
+	if (ret < 0) {
+		destroy_workqueue(afs_async_calls);
+		_leave(" = %d [socket]", ret);
+		return ret;
+	}
+
+	socket->sk->sk_allocation = GFP_NOFS;
+
+	/* bind the callback manager's address to make this a server socket */
+	srx.srx_family			= AF_RXRPC;
+	srx.srx_service			= CM_SERVICE;
+	srx.transport_type		= SOCK_DGRAM;
+	srx.transport_len		= sizeof(srx.transport.sin);
+	srx.transport.sin.sin_family	= AF_INET;
+	srx.transport.sin.sin_port	= htons(AFS_CM_PORT);
+	memset(&srx.transport.sin.sin_addr, 0,
+	       sizeof(srx.transport.sin.sin_addr));
+
+	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
+	if (ret < 0) {
+		sock_release(socket);
+		destroy_workqueue(afs_async_calls);
+		_leave(" = %d [bind]", ret);
+		return ret;
+	}
+
+	rxrpc_kernel_intercept_rx_messages(socket, afs_rx_interceptor);
+
+	afs_socket = socket;
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * close the RxRPC socket AFS was using
+ */
+void afs_close_socket(void)
+{
+	_enter("");
+
+	sock_release(afs_socket);
+
+	_debug("dework");
+	destroy_workqueue(afs_async_calls);
+
+	ASSERTCMP(atomic_read(&afs_outstanding_skbs), ==, 0);
+	ASSERTCMP(atomic_read(&afs_outstanding_calls), ==, 0);
+	_leave("");
+}
+
+/*
+ * note that the data in a socket buffer is now delivered and that the buffer
+ * should be freed
+ */
+static void afs_data_delivered(struct sk_buff *skb)
+{
+	if (!skb) {
+		_debug("DLVR NULL [%d]", atomic_read(&afs_outstanding_skbs));
+		dump_stack();
+	} else {
+		_debug("DLVR %p{%u} [%d]",
+		       skb, skb->mark, atomic_read(&afs_outstanding_skbs));
+		if (atomic_dec_return(&afs_outstanding_skbs) == -1)
+			BUG();
+		rxrpc_kernel_data_delivered(skb);
+	}
+}
+
+/*
+ * free a socket buffer
+ */
+static void afs_free_skb(struct sk_buff *skb)
+{
+	if (!skb) {
+		_debug("FREE NULL [%d]", atomic_read(&afs_outstanding_skbs));
+		dump_stack();
+	} else {
+		_debug("FREE %p{%u} [%d]",
+		       skb, skb->mark, atomic_read(&afs_outstanding_skbs));
+		if (atomic_dec_return(&afs_outstanding_skbs) == -1)
+			BUG();
+		rxrpc_kernel_free_skb(skb);
+	}
+}
+
+/*
+ * free a call
+ */
+static void afs_free_call(struct afs_call *call)
+{
+	_debug("DONE %p{%s} [%d]",
+	       call, call->type->name, atomic_read(&afs_outstanding_calls));
+	if (atomic_dec_return(&afs_outstanding_calls) == -1)
+		BUG();
+
+	ASSERTCMP(call->rxcall, ==, NULL);
+	ASSERT(!work_pending(&call->async_work));
+	ASSERT(skb_queue_empty(&call->rx_queue));
+	ASSERT(call->type->name != NULL);
+
+	kfree(call->request);
+	kfree(call);
+}
+
+/*
+ * End a call but do not free it
+ */
+static void afs_end_call_nofree(struct afs_call *call)
+{
+	if (call->rxcall) {
+		rxrpc_kernel_end_call(call->rxcall);
+		call->rxcall = NULL;
+	}
+	if (call->type->destructor)
+		call->type->destructor(call);
+}
+
+/*
+ * End a call and free it
+ */
+static void afs_end_call(struct afs_call *call)
+{
+	afs_end_call_nofree(call);
+	afs_free_call(call);
+}
+
+/*
+ * allocate a call with flat request and reply buffers
+ */
+struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
+				     size_t request_size, size_t reply_size)
+{
+	struct afs_call *call;
+
+	call = kzalloc(sizeof(*call), GFP_NOFS);
+	if (!call)
+		goto nomem_call;
+
+	_debug("CALL %p{%s} [%d]",
+	       call, type->name, atomic_read(&afs_outstanding_calls));
+	atomic_inc(&afs_outstanding_calls);
+
+	call->type = type;
+	call->request_size = request_size;
+	call->reply_max = reply_size;
+
+	if (request_size) {
+		call->request = kmalloc(request_size, GFP_NOFS);
+		if (!call->request)
+			goto nomem_free;
+	}
+
+	if (reply_size) {
+		call->buffer = kmalloc(reply_size, GFP_NOFS);
+		if (!call->buffer)
+			goto nomem_free;
+	}
+
+	init_waitqueue_head(&call->waitq);
+	skb_queue_head_init(&call->rx_queue);
+	return call;
+
+nomem_free:
+	afs_free_call(call);
+nomem_call:
+	return NULL;
+}
+
+/*
+ * clean up a call with flat buffer
+ */
+void afs_flat_call_destructor(struct afs_call *call)
+{
+	_enter("");
+
+	kfree(call->request);
+	call->request = NULL;
+	kfree(call->buffer);
+	call->buffer = NULL;
+}
+
+/*
+ * attach the data from a bunch of pages on an inode to a call
+ */
+static int afs_send_pages(struct afs_call *call, struct msghdr *msg,
+			  struct kvec *iov)
+{
+	struct page *pages[8];
+	unsigned count, n, loop, offset, to;
+	pgoff_t first = call->first, last = call->last;
+	int ret;
+
+	_enter("");
+
+	offset = call->first_offset;
+	call->first_offset = 0;
+
+	do {
+		_debug("attach %lx-%lx", first, last);
+
+		count = last - first + 1;
+		if (count > ARRAY_SIZE(pages))
+			count = ARRAY_SIZE(pages);
+		n = find_get_pages_contig(call->mapping, first, count, pages);
+		ASSERTCMP(n, ==, count);
+
+		loop = 0;
+		do {
+			msg->msg_flags = 0;
+			to = PAGE_SIZE;
+			if (first + loop >= last)
+				to = call->last_to;
+			else
+				msg->msg_flags = MSG_MORE;
+			iov->iov_base = kmap(pages[loop]) + offset;
+			iov->iov_len = to - offset;
+			offset = 0;
+
+			_debug("- range %u-%u%s",
+			       offset, to, msg->msg_flags ? " [more]" : "");
+			iov_iter_kvec(&msg->msg_iter, WRITE | ITER_KVEC,
+				      iov, 1, to - offset);
+
+			/* have to change the state *before* sending the last
+			 * packet as RxRPC might give us the reply before it
+			 * returns from sending the request */
+			if (first + loop >= last)
+				call->state = AFS_CALL_AWAIT_REPLY;
+			ret = rxrpc_kernel_send_data(call->rxcall, msg,
+						     to - offset);
+			kunmap(pages[loop]);
+			if (ret < 0)
+				break;
+		} while (++loop < count);
+		first += count;
+
+		for (loop = 0; loop < count; loop++)
+			put_page(pages[loop]);
+		if (ret < 0)
+			break;
+	} while (first <= last);
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * initiate a call
+ */
+int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
+		  const struct afs_wait_mode *wait_mode)
+{
+	struct sockaddr_rxrpc srx;
+	struct rxrpc_call *rxcall;
+	struct msghdr msg;
+	struct kvec iov[1];
+	int ret;
+	struct sk_buff *skb;
+
+	_enter("%x,{%d},", addr->s_addr, ntohs(call->port));
+
+	ASSERT(call->type != NULL);
+	ASSERT(call->type->name != NULL);
+
+	_debug("____MAKE %p{%s,%x} [%d]____",
+	       call, call->type->name, key_serial(call->key),
+	       atomic_read(&afs_outstanding_calls));
+
+	call->wait_mode = wait_mode;
+	call->async_workfn = afs_process_async_call;
+	INIT_WORK(&call->async_work, afs_async_workfn);
+
+	memset(&srx, 0, sizeof(srx));
+	srx.srx_family = AF_RXRPC;
+	srx.srx_service = call->service_id;
+	srx.transport_type = SOCK_DGRAM;
+	srx.transport_len = sizeof(srx.transport.sin);
+	srx.transport.sin.sin_family = AF_INET;
+	srx.transport.sin.sin_port = call->port;
+	memcpy(&srx.transport.sin.sin_addr, addr, 4);
+
+	/* create a call */
+	rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
+					 (unsigned long) call, gfp);
+	call->key = NULL;
+	if (IS_ERR(rxcall)) {
+		ret = PTR_ERR(rxcall);
+		goto error_kill_call;
+	}
+
+	call->rxcall = rxcall;
+
+	/* send the request */
+	iov[0].iov_base	= call->request;
+	iov[0].iov_len	= call->request_size;
+
+	msg.msg_name		= NULL;
+	msg.msg_namelen		= 0;
+	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1,
+		      call->request_size);
+	msg.msg_control		= NULL;
+	msg.msg_controllen	= 0;
+	msg.msg_flags		= (call->send_pages ? MSG_MORE : 0);
+
+	/* have to change the state *before* sending the last packet as RxRPC
+	 * might give us the reply before it returns from sending the
+	 * request */
+	if (!call->send_pages)
+		call->state = AFS_CALL_AWAIT_REPLY;
+	ret = rxrpc_kernel_send_data(rxcall, &msg, call->request_size);
+	if (ret < 0)
+		goto error_do_abort;
+
+	if (call->send_pages) {
+		ret = afs_send_pages(call, &msg, iov);
+		if (ret < 0)
+			goto error_do_abort;
+	}
+
+	/* at this point, an async call may no longer exist as it may have
+	 * already completed */
+	return wait_mode->wait(call);
+
+error_do_abort:
+	rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
+	while ((skb = skb_dequeue(&call->rx_queue)))
+		afs_free_skb(skb);
+error_kill_call:
+	afs_end_call(call);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * handles intercepted messages that were arriving in the socket's Rx queue
+ * - called with the socket receive queue lock held to ensure message ordering
+ * - called with softirqs disabled
+ */
+static void afs_rx_interceptor(struct sock *sk, unsigned long user_call_ID,
+			       struct sk_buff *skb)
+{
+	struct afs_call *call = (struct afs_call *) user_call_ID;
+
+	_enter("%p,,%u", call, skb->mark);
+
+	_debug("ICPT %p{%u} [%d]",
+	       skb, skb->mark, atomic_read(&afs_outstanding_skbs));
+
+	ASSERTCMP(sk, ==, afs_socket->sk);
+	atomic_inc(&afs_outstanding_skbs);
+
+	if (!call) {
+		/* its an incoming call for our callback service */
+		skb_queue_tail(&afs_incoming_calls, skb);
+		queue_work(afs_wq, &afs_collect_incoming_call_work);
+	} else {
+		/* route the messages directly to the appropriate call */
+		skb_queue_tail(&call->rx_queue, skb);
+		call->wait_mode->rx_wakeup(call);
+	}
+
+	_leave("");
+}
+
+/*
+ * deliver messages to a call
+ */
+static void afs_deliver_to_call(struct afs_call *call)
+{
+	struct sk_buff *skb;
+	bool last;
+	u32 abort_code;
+	int ret;
+
+	_enter("");
+
+	while ((call->state == AFS_CALL_AWAIT_REPLY ||
+		call->state == AFS_CALL_AWAIT_OP_ID ||
+		call->state == AFS_CALL_AWAIT_REQUEST ||
+		call->state == AFS_CALL_AWAIT_ACK) &&
+	       (skb = skb_dequeue(&call->rx_queue))) {
+		switch (skb->mark) {
+		case RXRPC_SKB_MARK_DATA:
+			_debug("Rcv DATA");
+			last = rxrpc_kernel_is_data_last(skb);
+			ret = call->type->deliver(call, skb, last);
+			switch (ret) {
+			case 0:
+				if (last &&
+				    call->state == AFS_CALL_AWAIT_REPLY)
+					call->state = AFS_CALL_COMPLETE;
+				break;
+			case -ENOTCONN:
+				abort_code = RX_CALL_DEAD;
+				goto do_abort;
+			case -ENOTSUPP:
+				abort_code = RX_INVALID_OPERATION;
+				goto do_abort;
+			default:
+				abort_code = RXGEN_CC_UNMARSHAL;
+				if (call->state != AFS_CALL_AWAIT_REPLY)
+					abort_code = RXGEN_SS_UNMARSHAL;
+			do_abort:
+				rxrpc_kernel_abort_call(call->rxcall,
+							abort_code);
+				call->error = ret;
+				call->state = AFS_CALL_ERROR;
+				break;
+			}
+			afs_data_delivered(skb);
+			skb = NULL;
+			continue;
+		case RXRPC_SKB_MARK_FINAL_ACK:
+			_debug("Rcv ACK");
+			call->state = AFS_CALL_COMPLETE;
+			break;
+		case RXRPC_SKB_MARK_BUSY:
+			_debug("Rcv BUSY");
+			call->error = -EBUSY;
+			call->state = AFS_CALL_BUSY;
+			break;
+		case RXRPC_SKB_MARK_REMOTE_ABORT:
+			abort_code = rxrpc_kernel_get_abort_code(skb);
+			call->error = call->type->abort_to_error(abort_code);
+			call->state = AFS_CALL_ABORTED;
+			_debug("Rcv ABORT %u -> %d", abort_code, call->error);
+			break;
+		case RXRPC_SKB_MARK_NET_ERROR:
+			call->error = -rxrpc_kernel_get_error_number(skb);
+			call->state = AFS_CALL_ERROR;
+			_debug("Rcv NET ERROR %d", call->error);
+			break;
+		case RXRPC_SKB_MARK_LOCAL_ERROR:
+			call->error = -rxrpc_kernel_get_error_number(skb);
+			call->state = AFS_CALL_ERROR;
+			_debug("Rcv LOCAL ERROR %d", call->error);
+			break;
+		default:
+			BUG();
+			break;
+		}
+
+		afs_free_skb(skb);
+	}
+
+	/* make sure the queue is empty if the call is done with (we might have
+	 * aborted the call early because of an unmarshalling error) */
+	if (call->state >= AFS_CALL_COMPLETE) {
+		while ((skb = skb_dequeue(&call->rx_queue)))
+			afs_free_skb(skb);
+		if (call->incoming)
+			afs_end_call(call);
+	}
+
+	_leave("");
+}
+
+/*
+ * wait synchronously for a call to complete
+ */
+static int afs_wait_for_call_to_complete(struct afs_call *call)
+{
+	struct sk_buff *skb;
+	int ret;
+
+	DECLARE_WAITQUEUE(myself, current);
+
+	_enter("");
+
+	add_wait_queue(&call->waitq, &myself);
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		/* deliver any messages that are in the queue */
+		if (!skb_queue_empty(&call->rx_queue)) {
+			__set_current_state(TASK_RUNNING);
+			afs_deliver_to_call(call);
+			continue;
+		}
+
+		ret = call->error;
+		if (call->state >= AFS_CALL_COMPLETE)
+			break;
+		ret = -EINTR;
+		if (signal_pending(current))
+			break;
+		schedule();
+	}
+
+	remove_wait_queue(&call->waitq, &myself);
+	__set_current_state(TASK_RUNNING);
+
+	/* kill the call */
+	if (call->state < AFS_CALL_COMPLETE) {
+		_debug("call incomplete");
+		rxrpc_kernel_abort_call(call->rxcall, RX_CALL_DEAD);
+		while ((skb = skb_dequeue(&call->rx_queue)))
+			afs_free_skb(skb);
+	}
+
+	_debug("call complete");
+	afs_end_call(call);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * wake up a waiting call
+ */
+static void afs_wake_up_call_waiter(struct afs_call *call)
+{
+	wake_up(&call->waitq);
+}
+
+/*
+ * wake up an asynchronous call
+ */
+static void afs_wake_up_async_call(struct afs_call *call)
+{
+	_enter("");
+	queue_work(afs_async_calls, &call->async_work);
+}
+
+/*
+ * put a call into asynchronous mode
+ * - mustn't touch the call descriptor as the call my have completed by the
+ *   time we get here
+ */
+static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
+{
+	_enter("");
+	return -EINPROGRESS;
+}
+
+/*
+ * delete an asynchronous call
+ */
+static void afs_delete_async_call(struct afs_call *call)
+{
+	_enter("");
+
+	afs_free_call(call);
+
+	_leave("");
+}
+
+/*
+ * perform processing on an asynchronous call
+ * - on a multiple-thread workqueue this work item may try to run on several
+ *   CPUs at the same time
+ */
+static void afs_process_async_call(struct afs_call *call)
+{
+	_enter("");
+
+	if (!skb_queue_empty(&call->rx_queue))
+		afs_deliver_to_call(call);
+
+	if (call->state >= AFS_CALL_COMPLETE && call->wait_mode) {
+		if (call->wait_mode->async_complete)
+			call->wait_mode->async_complete(call->reply,
+							call->error);
+		call->reply = NULL;
+
+		/* kill the call */
+		afs_end_call_nofree(call);
+
+		/* we can't just delete the call because the work item may be
+		 * queued */
+		call->async_workfn = afs_delete_async_call;
+		queue_work(afs_async_calls, &call->async_work);
+	}
+
+	_leave("");
+}
+
+/*
+ * empty a socket buffer into a flat reply buffer
+ */
+void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
+{
+	size_t len = skb->len;
+
+	if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
+		BUG();
+	call->reply_size += len;
+}
+
+/*
+ * accept the backlog of incoming calls
+ */
+static void afs_collect_incoming_call(struct work_struct *work)
+{
+	struct rxrpc_call *rxcall;
+	struct afs_call *call = NULL;
+	struct sk_buff *skb;
+
+	while ((skb = skb_dequeue(&afs_incoming_calls))) {
+		_debug("new call");
+
+		/* don't need the notification */
+		afs_free_skb(skb);
+
+		if (!call) {
+			call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
+			if (!call) {
+				rxrpc_kernel_reject_call(afs_socket);
+				return;
+			}
+
+			call->async_workfn = afs_process_async_call;
+			INIT_WORK(&call->async_work, afs_async_workfn);
+			call->wait_mode = &afs_async_incoming_call;
+			call->type = &afs_RXCMxxxx;
+			init_waitqueue_head(&call->waitq);
+			skb_queue_head_init(&call->rx_queue);
+			call->state = AFS_CALL_AWAIT_OP_ID;
+
+			_debug("CALL %p{%s} [%d]",
+			       call, call->type->name,
+			       atomic_read(&afs_outstanding_calls));
+			atomic_inc(&afs_outstanding_calls);
+		}
+
+		rxcall = rxrpc_kernel_accept_call(afs_socket,
+						  (unsigned long) call);
+		if (!IS_ERR(rxcall)) {
+			call->rxcall = rxcall;
+			call = NULL;
+		}
+	}
+
+	if (call)
+		afs_free_call(call);
+}
+
+/*
+ * grab the operation ID from an incoming cache manager call
+ */
+static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
+				bool last)
+{
+	size_t len = skb->len;
+	void *oibuf = (void *) &call->operation_ID;
+
+	_enter("{%u},{%zu},%d", call->offset, len, last);
+
+	ASSERTCMP(call->offset, <, 4);
+
+	/* the operation ID forms the first four bytes of the request data */
+	len = min_t(size_t, len, 4 - call->offset);
+	if (skb_copy_bits(skb, 0, oibuf + call->offset, len) < 0)
+		BUG();
+	if (!pskb_pull(skb, len))
+		BUG();
+	call->offset += len;
+
+	if (call->offset < 4) {
+		if (last) {
+			_leave(" = -EBADMSG [op ID short]");
+			return -EBADMSG;
+		}
+		_leave(" = 0 [incomplete]");
+		return 0;
+	}
+
+	call->state = AFS_CALL_AWAIT_REQUEST;
+
+	/* ask the cache manager to route the call (it'll change the call type
+	 * if successful) */
+	if (!afs_cm_incoming_call(call))
+		return -ENOTSUPP;
+
+	/* pass responsibility for the remainer of this message off to the
+	 * cache manager op */
+	return call->type->deliver(call, skb, last);
+}
+
+/*
+ * send an empty reply
+ */
+void afs_send_empty_reply(struct afs_call *call)
+{
+	struct msghdr msg;
+
+	_enter("");
+
+	msg.msg_name		= NULL;
+	msg.msg_namelen		= 0;
+	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
+	msg.msg_control		= NULL;
+	msg.msg_controllen	= 0;
+	msg.msg_flags		= 0;
+
+	call->state = AFS_CALL_AWAIT_ACK;
+	switch (rxrpc_kernel_send_data(call->rxcall, &msg, 0)) {
+	case 0:
+		_leave(" [replied]");
+		return;
+
+	case -ENOMEM:
+		_debug("oom");
+		rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
+	default:
+		afs_end_call(call);
+		_leave(" [error]");
+		return;
+	}
+}
+
+/*
+ * send a simple reply
+ */
+void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
+{
+	struct msghdr msg;
+	struct kvec iov[1];
+	int n;
+
+	_enter("");
+
+	iov[0].iov_base		= (void *) buf;
+	iov[0].iov_len		= len;
+	msg.msg_name		= NULL;
+	msg.msg_namelen		= 0;
+	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
+	msg.msg_control		= NULL;
+	msg.msg_controllen	= 0;
+	msg.msg_flags		= 0;
+
+	call->state = AFS_CALL_AWAIT_ACK;
+	n = rxrpc_kernel_send_data(call->rxcall, &msg, len);
+	if (n >= 0) {
+		/* Success */
+		_leave(" [replied]");
+		return;
+	}
+
+	if (n == -ENOMEM) {
+		_debug("oom");
+		rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
+	}
+	afs_end_call(call);
+	_leave(" [error]");
+}
+
+/*
+ * extract a piece of data from the received data socket buffers
+ */
+int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
+		     bool last, void *buf, size_t count)
+{
+	size_t len = skb->len;
+
+	_enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
+
+	ASSERTCMP(call->offset, <, count);
+
+	len = min_t(size_t, len, count - call->offset);
+	if (skb_copy_bits(skb, 0, buf + call->offset, len) < 0 ||
+	    !pskb_pull(skb, len))
+		BUG();
+	call->offset += len;
+
+	if (call->offset < count) {
+		if (last) {
+			_leave(" = -EBADMSG [%d < %zu]", call->offset, count);
+			return -EBADMSG;
+		}
+		_leave(" = -EAGAIN");
+		return -EAGAIN;
+	}
+	return 0;
+}