Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 945 insertions, 0 deletions

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
new file mode 100644
index 0000000000..d642d06a45
--- /dev/null
+++ b/fs/afs/rxrpc.c
@@ -0,0 +1,945 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* 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)
+ */
+
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "internal.h"
+#include "afs_cm.h"
+#include "protocol_yfs.h"
+#define RXRPC_TRACE_ONLY_DEFINE_ENUMS
+#include <trace/events/rxrpc.h>
+
+struct workqueue_struct *afs_async_calls;
+
+static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
+static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
+static void afs_process_async_call(struct work_struct *);
+static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
+static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
+static int afs_deliver_cm_op_id(struct afs_call *);
+
+/* asynchronous incoming call initial processing */
+static const struct afs_call_type afs_RXCMxxxx = {
+	.name		= "CB.xxxx",
+	.deliver	= afs_deliver_cm_op_id,
+};
+
+/*
+ * 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(struct afs_net *net)
+{
+	struct sockaddr_rxrpc srx;
+	struct socket *socket;
+	int ret;
+
+	_enter("");
+
+	ret = sock_create_kern(net->net, AF_RXRPC, SOCK_DGRAM, PF_INET6, &socket);
+	if (ret < 0)
+		goto error_1;
+
+	socket->sk->sk_allocation = GFP_NOFS;
+
+	/* bind the callback manager's address to make this a server socket */
+	memset(&srx, 0, sizeof(srx));
+	srx.srx_family			= AF_RXRPC;
+	srx.srx_service			= CM_SERVICE;
+	srx.transport_type		= SOCK_DGRAM;
+	srx.transport_len		= sizeof(srx.transport.sin6);
+	srx.transport.sin6.sin6_family	= AF_INET6;
+	srx.transport.sin6.sin6_port	= htons(AFS_CM_PORT);
+
+	ret = rxrpc_sock_set_min_security_level(socket->sk,
+						RXRPC_SECURITY_ENCRYPT);
+	if (ret < 0)
+		goto error_2;
+
+	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
+	if (ret == -EADDRINUSE) {
+		srx.transport.sin6.sin6_port = 0;
+		ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
+	}
+	if (ret < 0)
+		goto error_2;
+
+	srx.srx_service = YFS_CM_SERVICE;
+	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
+	if (ret < 0)
+		goto error_2;
+
+	/* Ideally, we'd turn on service upgrade here, but we can't because
+	 * OpenAFS is buggy and leaks the userStatus field from packet to
+	 * packet and between FS packets and CB packets - so if we try to do an
+	 * upgrade on an FS packet, OpenAFS will leak that into the CB packet
+	 * it sends back to us.
+	 */
+
+	rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
+					   afs_rx_discard_new_call);
+
+	ret = kernel_listen(socket, INT_MAX);
+	if (ret < 0)
+		goto error_2;
+
+	net->socket = socket;
+	afs_charge_preallocation(&net->charge_preallocation_work);
+	_leave(" = 0");
+	return 0;
+
+error_2:
+	sock_release(socket);
+error_1:
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * close the RxRPC socket AFS was using
+ */
+void afs_close_socket(struct afs_net *net)
+{
+	_enter("");
+
+	kernel_listen(net->socket, 0);
+	flush_workqueue(afs_async_calls);
+
+	if (net->spare_incoming_call) {
+		afs_put_call(net->spare_incoming_call);
+		net->spare_incoming_call = NULL;
+	}
+
+	_debug("outstanding %u", atomic_read(&net->nr_outstanding_calls));
+	wait_var_event(&net->nr_outstanding_calls,
+		       !atomic_read(&net->nr_outstanding_calls));
+	_debug("no outstanding calls");
+
+	kernel_sock_shutdown(net->socket, SHUT_RDWR);
+	flush_workqueue(afs_async_calls);
+	sock_release(net->socket);
+
+	_debug("dework");
+	_leave("");
+}
+
+/*
+ * Allocate a call.
+ */
+static struct afs_call *afs_alloc_call(struct afs_net *net,
+				       const struct afs_call_type *type,
+				       gfp_t gfp)
+{
+	struct afs_call *call;
+	int o;
+
+	call = kzalloc(sizeof(*call), gfp);
+	if (!call)
+		return NULL;
+
+	call->type = type;
+	call->net = net;
+	call->debug_id = atomic_inc_return(&rxrpc_debug_id);
+	refcount_set(&call->ref, 1);
+	INIT_WORK(&call->async_work, afs_process_async_call);
+	init_waitqueue_head(&call->waitq);
+	spin_lock_init(&call->state_lock);
+	call->iter = &call->def_iter;
+
+	o = atomic_inc_return(&net->nr_outstanding_calls);
+	trace_afs_call(call->debug_id, afs_call_trace_alloc, 1, o,
+		       __builtin_return_address(0));
+	return call;
+}
+
+/*
+ * Dispose of a reference on a call.
+ */
+void afs_put_call(struct afs_call *call)
+{
+	struct afs_net *net = call->net;
+	unsigned int debug_id = call->debug_id;
+	bool zero;
+	int r, o;
+
+	zero = __refcount_dec_and_test(&call->ref, &r);
+	o = atomic_read(&net->nr_outstanding_calls);
+	trace_afs_call(debug_id, afs_call_trace_put, r - 1, o,
+		       __builtin_return_address(0));
+
+	if (zero) {
+		ASSERT(!work_pending(&call->async_work));
+		ASSERT(call->type->name != NULL);
+
+		if (call->rxcall) {
+			rxrpc_kernel_shutdown_call(net->socket, call->rxcall);
+			rxrpc_kernel_put_call(net->socket, call->rxcall);
+			call->rxcall = NULL;
+		}
+		if (call->type->destructor)
+			call->type->destructor(call);
+
+		afs_unuse_server_notime(call->net, call->server, afs_server_trace_put_call);
+		afs_put_addrlist(call->alist);
+		kfree(call->request);
+
+		trace_afs_call(call->debug_id, afs_call_trace_free, 0, o,
+			       __builtin_return_address(0));
+		kfree(call);
+
+		o = atomic_dec_return(&net->nr_outstanding_calls);
+		if (o == 0)
+			wake_up_var(&net->nr_outstanding_calls);
+	}
+}
+
+static struct afs_call *afs_get_call(struct afs_call *call,
+				     enum afs_call_trace why)
+{
+	int r;
+
+	__refcount_inc(&call->ref, &r);
+
+	trace_afs_call(call->debug_id, why, r + 1,
+		       atomic_read(&call->net->nr_outstanding_calls),
+		       __builtin_return_address(0));
+	return call;
+}
+
+/*
+ * Queue the call for actual work.
+ */
+static void afs_queue_call_work(struct afs_call *call)
+{
+	if (call->type->work) {
+		INIT_WORK(&call->work, call->type->work);
+
+		afs_get_call(call, afs_call_trace_work);
+		if (!queue_work(afs_wq, &call->work))
+			afs_put_call(call);
+	}
+}
+
+/*
+ * allocate a call with flat request and reply buffers
+ */
+struct afs_call *afs_alloc_flat_call(struct afs_net *net,
+				     const struct afs_call_type *type,
+				     size_t request_size, size_t reply_max)
+{
+	struct afs_call *call;
+
+	call = afs_alloc_call(net, type, GFP_NOFS);
+	if (!call)
+		goto nomem_call;
+
+	if (request_size) {
+		call->request_size = request_size;
+		call->request = kmalloc(request_size, GFP_NOFS);
+		if (!call->request)
+			goto nomem_free;
+	}
+
+	if (reply_max) {
+		call->reply_max = reply_max;
+		call->buffer = kmalloc(reply_max, GFP_NOFS);
+		if (!call->buffer)
+			goto nomem_free;
+	}
+
+	afs_extract_to_buf(call, call->reply_max);
+	call->operation_ID = type->op;
+	init_waitqueue_head(&call->waitq);
+	return call;
+
+nomem_free:
+	afs_put_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;
+}
+
+/*
+ * Advance the AFS call state when the RxRPC call ends the transmit phase.
+ */
+static void afs_notify_end_request_tx(struct sock *sock,
+				      struct rxrpc_call *rxcall,
+				      unsigned long call_user_ID)
+{
+	struct afs_call *call = (struct afs_call *)call_user_ID;
+
+	afs_set_call_state(call, AFS_CALL_CL_REQUESTING, AFS_CALL_CL_AWAIT_REPLY);
+}
+
+/*
+ * Initiate a call and synchronously queue up the parameters for dispatch.  Any
+ * error is stored into the call struct, which the caller must check for.
+ */
+void afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call, gfp_t gfp)
+{
+	struct sockaddr_rxrpc *srx = &ac->alist->addrs[ac->index];
+	struct rxrpc_call *rxcall;
+	struct msghdr msg;
+	struct kvec iov[1];
+	size_t len;
+	s64 tx_total_len;
+	int ret;
+
+	_enter(",{%pISp},", &srx->transport);
+
+	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(&call->net->nr_outstanding_calls));
+
+	call->addr_ix = ac->index;
+	call->alist = afs_get_addrlist(ac->alist);
+
+	/* Work out the length we're going to transmit.  This is awkward for
+	 * calls such as FS.StoreData where there's an extra injection of data
+	 * after the initial fixed part.
+	 */
+	tx_total_len = call->request_size;
+	if (call->write_iter)
+		tx_total_len += iov_iter_count(call->write_iter);
+
+	/* If the call is going to be asynchronous, we need an extra ref for
+	 * the call to hold itself so the caller need not hang on to its ref.
+	 */
+	if (call->async) {
+		afs_get_call(call, afs_call_trace_get);
+		call->drop_ref = true;
+	}
+
+	/* create a call */
+	rxcall = rxrpc_kernel_begin_call(call->net->socket, srx, call->key,
+					 (unsigned long)call,
+					 tx_total_len,
+					 call->max_lifespan,
+					 gfp,
+					 (call->async ?
+					  afs_wake_up_async_call :
+					  afs_wake_up_call_waiter),
+					 call->upgrade,
+					 (call->intr ? RXRPC_PREINTERRUPTIBLE :
+					  RXRPC_UNINTERRUPTIBLE),
+					 call->debug_id);
+	if (IS_ERR(rxcall)) {
+		ret = PTR_ERR(rxcall);
+		call->error = ret;
+		goto error_kill_call;
+	}
+
+	call->rxcall = rxcall;
+	call->issue_time = ktime_get_real();
+
+	/* 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, ITER_SOURCE, iov, 1, call->request_size);
+	msg.msg_control		= NULL;
+	msg.msg_controllen	= 0;
+	msg.msg_flags		= MSG_WAITALL | (call->write_iter ? MSG_MORE : 0);
+
+	ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
+				     &msg, call->request_size,
+				     afs_notify_end_request_tx);
+	if (ret < 0)
+		goto error_do_abort;
+
+	if (call->write_iter) {
+		msg.msg_iter = *call->write_iter;
+		msg.msg_flags &= ~MSG_MORE;
+		trace_afs_send_data(call, &msg);
+
+		ret = rxrpc_kernel_send_data(call->net->socket,
+					     call->rxcall, &msg,
+					     iov_iter_count(&msg.msg_iter),
+					     afs_notify_end_request_tx);
+		*call->write_iter = msg.msg_iter;
+
+		trace_afs_sent_data(call, &msg, ret);
+		if (ret < 0)
+			goto error_do_abort;
+	}
+
+	/* Note that at this point, we may have received the reply or an abort
+	 * - and an asynchronous call may already have completed.
+	 *
+	 * afs_wait_for_call_to_complete(call, ac)
+	 * must be called to synchronously clean up.
+	 */
+	return;
+
+error_do_abort:
+	if (ret != -ECONNABORTED) {
+		rxrpc_kernel_abort_call(call->net->socket, rxcall,
+					RX_USER_ABORT, ret,
+					afs_abort_send_data_error);
+	} else {
+		len = 0;
+		iov_iter_kvec(&msg.msg_iter, ITER_DEST, NULL, 0, 0);
+		rxrpc_kernel_recv_data(call->net->socket, rxcall,
+				       &msg.msg_iter, &len, false,
+				       &call->abort_code, &call->service_id);
+		ac->abort_code = call->abort_code;
+		ac->responded = true;
+	}
+	call->error = ret;
+	trace_afs_call_done(call);
+error_kill_call:
+	if (call->type->done)
+		call->type->done(call);
+
+	/* We need to dispose of the extra ref we grabbed for an async call.
+	 * The call, however, might be queued on afs_async_calls and we need to
+	 * make sure we don't get any more notifications that might requeue it.
+	 */
+	if (call->rxcall)
+		rxrpc_kernel_shutdown_call(call->net->socket, call->rxcall);
+	if (call->async) {
+		if (cancel_work_sync(&call->async_work))
+			afs_put_call(call);
+		afs_set_call_complete(call, ret, 0);
+	}
+
+	ac->error = ret;
+	call->state = AFS_CALL_COMPLETE;
+	_leave(" = %d", ret);
+}
+
+/*
+ * Log remote abort codes that indicate that we have a protocol disagreement
+ * with the server.
+ */
+static void afs_log_error(struct afs_call *call, s32 remote_abort)
+{
+	static int max = 0;
+	const char *msg;
+	int m;
+
+	switch (remote_abort) {
+	case RX_EOF:		 msg = "unexpected EOF";	break;
+	case RXGEN_CC_MARSHAL:	 msg = "client marshalling";	break;
+	case RXGEN_CC_UNMARSHAL: msg = "client unmarshalling";	break;
+	case RXGEN_SS_MARSHAL:	 msg = "server marshalling";	break;
+	case RXGEN_SS_UNMARSHAL: msg = "server unmarshalling";	break;
+	case RXGEN_DECODE:	 msg = "opcode decode";		break;
+	case RXGEN_SS_XDRFREE:	 msg = "server XDR cleanup";	break;
+	case RXGEN_CC_XDRFREE:	 msg = "client XDR cleanup";	break;
+	case -32:		 msg = "insufficient data";	break;
+	default:
+		return;
+	}
+
+	m = max;
+	if (m < 3) {
+		max = m + 1;
+		pr_notice("kAFS: Peer reported %s failure on %s [%pISp]\n",
+			  msg, call->type->name,
+			  &call->alist->addrs[call->addr_ix].transport);
+	}
+}
+
+/*
+ * deliver messages to a call
+ */
+static void afs_deliver_to_call(struct afs_call *call)
+{
+	enum afs_call_state state;
+	size_t len;
+	u32 abort_code, remote_abort = 0;
+	int ret;
+
+	_enter("%s", call->type->name);
+
+	while (state = READ_ONCE(call->state),
+	       state == AFS_CALL_CL_AWAIT_REPLY ||
+	       state == AFS_CALL_SV_AWAIT_OP_ID ||
+	       state == AFS_CALL_SV_AWAIT_REQUEST ||
+	       state == AFS_CALL_SV_AWAIT_ACK
+	       ) {
+		if (state == AFS_CALL_SV_AWAIT_ACK) {
+			len = 0;
+			iov_iter_kvec(&call->def_iter, ITER_DEST, NULL, 0, 0);
+			ret = rxrpc_kernel_recv_data(call->net->socket,
+						     call->rxcall, &call->def_iter,
+						     &len, false, &remote_abort,
+						     &call->service_id);
+			trace_afs_receive_data(call, &call->def_iter, false, ret);
+
+			if (ret == -EINPROGRESS || ret == -EAGAIN)
+				return;
+			if (ret < 0 || ret == 1) {
+				if (ret == 1)
+					ret = 0;
+				goto call_complete;
+			}
+			return;
+		}
+
+		ret = call->type->deliver(call);
+		state = READ_ONCE(call->state);
+		if (ret == 0 && call->unmarshalling_error)
+			ret = -EBADMSG;
+		switch (ret) {
+		case 0:
+			afs_queue_call_work(call);
+			if (state == AFS_CALL_CL_PROC_REPLY) {
+				if (call->op)
+					set_bit(AFS_SERVER_FL_MAY_HAVE_CB,
+						&call->op->server->flags);
+				goto call_complete;
+			}
+			ASSERTCMP(state, >, AFS_CALL_CL_PROC_REPLY);
+			goto done;
+		case -EINPROGRESS:
+		case -EAGAIN:
+			goto out;
+		case -ECONNABORTED:
+			ASSERTCMP(state, ==, AFS_CALL_COMPLETE);
+			afs_log_error(call, call->abort_code);
+			goto done;
+		case -ENOTSUPP:
+			abort_code = RXGEN_OPCODE;
+			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
+						abort_code, ret,
+						afs_abort_op_not_supported);
+			goto local_abort;
+		case -EIO:
+			pr_err("kAFS: Call %u in bad state %u\n",
+			       call->debug_id, state);
+			fallthrough;
+		case -ENODATA:
+		case -EBADMSG:
+		case -EMSGSIZE:
+		case -ENOMEM:
+		case -EFAULT:
+			abort_code = RXGEN_CC_UNMARSHAL;
+			if (state != AFS_CALL_CL_AWAIT_REPLY)
+				abort_code = RXGEN_SS_UNMARSHAL;
+			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
+						abort_code, ret,
+						afs_abort_unmarshal_error);
+			goto local_abort;
+		default:
+			abort_code = RX_CALL_DEAD;
+			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
+						abort_code, ret,
+						afs_abort_general_error);
+			goto local_abort;
+		}
+	}
+
+done:
+	if (call->type->done)
+		call->type->done(call);
+out:
+	_leave("");
+	return;
+
+local_abort:
+	abort_code = 0;
+call_complete:
+	afs_set_call_complete(call, ret, remote_abort);
+	state = AFS_CALL_COMPLETE;
+	goto done;
+}
+
+/*
+ * Wait synchronously for a call to complete and clean up the call struct.
+ */
+long afs_wait_for_call_to_complete(struct afs_call *call,
+				   struct afs_addr_cursor *ac)
+{
+	long ret;
+	bool rxrpc_complete = false;
+
+	DECLARE_WAITQUEUE(myself, current);
+
+	_enter("");
+
+	ret = call->error;
+	if (ret < 0)
+		goto out;
+
+	add_wait_queue(&call->waitq, &myself);
+	for (;;) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+
+		/* deliver any messages that are in the queue */
+		if (!afs_check_call_state(call, AFS_CALL_COMPLETE) &&
+		    call->need_attention) {
+			call->need_attention = false;
+			__set_current_state(TASK_RUNNING);
+			afs_deliver_to_call(call);
+			continue;
+		}
+
+		if (afs_check_call_state(call, AFS_CALL_COMPLETE))
+			break;
+
+		if (!rxrpc_kernel_check_life(call->net->socket, call->rxcall)) {
+			/* rxrpc terminated the call. */
+			rxrpc_complete = true;
+			break;
+		}
+
+		schedule();
+	}
+
+	remove_wait_queue(&call->waitq, &myself);
+	__set_current_state(TASK_RUNNING);
+
+	if (!afs_check_call_state(call, AFS_CALL_COMPLETE)) {
+		if (rxrpc_complete) {
+			afs_set_call_complete(call, call->error, call->abort_code);
+		} else {
+			/* Kill off the call if it's still live. */
+			_debug("call interrupted");
+			if (rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
+						    RX_USER_ABORT, -EINTR,
+						    afs_abort_interrupted))
+				afs_set_call_complete(call, -EINTR, 0);
+		}
+	}
+
+	spin_lock_bh(&call->state_lock);
+	ac->abort_code = call->abort_code;
+	ac->error = call->error;
+	spin_unlock_bh(&call->state_lock);
+
+	ret = ac->error;
+	switch (ret) {
+	case 0:
+		ret = call->ret0;
+		call->ret0 = 0;
+
+		fallthrough;
+	case -ECONNABORTED:
+		ac->responded = true;
+		break;
+	}
+
+out:
+	_debug("call complete");
+	afs_put_call(call);
+	_leave(" = %p", (void *)ret);
+	return ret;
+}
+
+/*
+ * wake up a waiting call
+ */
+static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
+				    unsigned long call_user_ID)
+{
+	struct afs_call *call = (struct afs_call *)call_user_ID;
+
+	call->need_attention = true;
+	wake_up(&call->waitq);
+}
+
+/*
+ * wake up an asynchronous call
+ */
+static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
+				   unsigned long call_user_ID)
+{
+	struct afs_call *call = (struct afs_call *)call_user_ID;
+	int r;
+
+	trace_afs_notify_call(rxcall, call);
+	call->need_attention = true;
+
+	if (__refcount_inc_not_zero(&call->ref, &r)) {
+		trace_afs_call(call->debug_id, afs_call_trace_wake, r + 1,
+			       atomic_read(&call->net->nr_outstanding_calls),
+			       __builtin_return_address(0));
+
+		if (!queue_work(afs_async_calls, &call->async_work))
+			afs_put_call(call);
+	}
+}
+
+/*
+ * Perform I/O processing on an asynchronous call.  The work item carries a ref
+ * to the call struct that we either need to release or to pass on.
+ */
+static void afs_process_async_call(struct work_struct *work)
+{
+	struct afs_call *call = container_of(work, struct afs_call, async_work);
+
+	_enter("");
+
+	if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
+		call->need_attention = false;
+		afs_deliver_to_call(call);
+	}
+
+	afs_put_call(call);
+	_leave("");
+}
+
+static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
+{
+	struct afs_call *call = (struct afs_call *)user_call_ID;
+
+	call->rxcall = rxcall;
+}
+
+/*
+ * Charge the incoming call preallocation.
+ */
+void afs_charge_preallocation(struct work_struct *work)
+{
+	struct afs_net *net =
+		container_of(work, struct afs_net, charge_preallocation_work);
+	struct afs_call *call = net->spare_incoming_call;
+
+	for (;;) {
+		if (!call) {
+			call = afs_alloc_call(net, &afs_RXCMxxxx, GFP_KERNEL);
+			if (!call)
+				break;
+
+			call->drop_ref = true;
+			call->async = true;
+			call->state = AFS_CALL_SV_AWAIT_OP_ID;
+			init_waitqueue_head(&call->waitq);
+			afs_extract_to_tmp(call);
+		}
+
+		if (rxrpc_kernel_charge_accept(net->socket,
+					       afs_wake_up_async_call,
+					       afs_rx_attach,
+					       (unsigned long)call,
+					       GFP_KERNEL,
+					       call->debug_id) < 0)
+			break;
+		call = NULL;
+	}
+	net->spare_incoming_call = call;
+}
+
+/*
+ * Discard a preallocated call when a socket is shut down.
+ */
+static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
+				    unsigned long user_call_ID)
+{
+	struct afs_call *call = (struct afs_call *)user_call_ID;
+
+	call->rxcall = NULL;
+	afs_put_call(call);
+}
+
+/*
+ * Notification of an incoming call.
+ */
+static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
+			    unsigned long user_call_ID)
+{
+	struct afs_net *net = afs_sock2net(sk);
+
+	queue_work(afs_wq, &net->charge_preallocation_work);
+}
+
+/*
+ * Grab the operation ID from an incoming cache manager call.  The socket
+ * buffer is discarded on error or if we don't yet have sufficient data.
+ */
+static int afs_deliver_cm_op_id(struct afs_call *call)
+{
+	int ret;
+
+	_enter("{%zu}", iov_iter_count(call->iter));
+
+	/* the operation ID forms the first four bytes of the request data */
+	ret = afs_extract_data(call, true);
+	if (ret < 0)
+		return ret;
+
+	call->operation_ID = ntohl(call->tmp);
+	afs_set_call_state(call, AFS_CALL_SV_AWAIT_OP_ID, AFS_CALL_SV_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;
+
+	trace_afs_cb_call(call);
+
+	/* pass responsibility for the remainer of this message off to the
+	 * cache manager op */
+	return call->type->deliver(call);
+}
+
+/*
+ * Advance the AFS call state when an RxRPC service call ends the transmit
+ * phase.
+ */
+static void afs_notify_end_reply_tx(struct sock *sock,
+				    struct rxrpc_call *rxcall,
+				    unsigned long call_user_ID)
+{
+	struct afs_call *call = (struct afs_call *)call_user_ID;
+
+	afs_set_call_state(call, AFS_CALL_SV_REPLYING, AFS_CALL_SV_AWAIT_ACK);
+}
+
+/*
+ * send an empty reply
+ */
+void afs_send_empty_reply(struct afs_call *call)
+{
+	struct afs_net *net = call->net;
+	struct msghdr msg;
+
+	_enter("");
+
+	rxrpc_kernel_set_tx_length(net->socket, call->rxcall, 0);
+
+	msg.msg_name		= NULL;
+	msg.msg_namelen		= 0;
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, NULL, 0, 0);
+	msg.msg_control		= NULL;
+	msg.msg_controllen	= 0;
+	msg.msg_flags		= 0;
+
+	switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, 0,
+				       afs_notify_end_reply_tx)) {
+	case 0:
+		_leave(" [replied]");
+		return;
+
+	case -ENOMEM:
+		_debug("oom");
+		rxrpc_kernel_abort_call(net->socket, call->rxcall,
+					RXGEN_SS_MARSHAL, -ENOMEM,
+					afs_abort_oom);
+		fallthrough;
+	default:
+		_leave(" [error]");
+		return;
+	}
+}
+
+/*
+ * send a simple reply
+ */
+void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
+{
+	struct afs_net *net = call->net;
+	struct msghdr msg;
+	struct kvec iov[1];
+	int n;
+
+	_enter("");
+
+	rxrpc_kernel_set_tx_length(net->socket, call->rxcall, len);
+
+	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, ITER_SOURCE, iov, 1, len);
+	msg.msg_control		= NULL;
+	msg.msg_controllen	= 0;
+	msg.msg_flags		= 0;
+
+	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
+				   afs_notify_end_reply_tx);
+	if (n >= 0) {
+		/* Success */
+		_leave(" [replied]");
+		return;
+	}
+
+	if (n == -ENOMEM) {
+		_debug("oom");
+		rxrpc_kernel_abort_call(net->socket, call->rxcall,
+					RXGEN_SS_MARSHAL, -ENOMEM,
+					afs_abort_oom);
+	}
+	_leave(" [error]");
+}
+
+/*
+ * Extract a piece of data from the received data socket buffers.
+ */
+int afs_extract_data(struct afs_call *call, bool want_more)
+{
+	struct afs_net *net = call->net;
+	struct iov_iter *iter = call->iter;
+	enum afs_call_state state;
+	u32 remote_abort = 0;
+	int ret;
+
+	_enter("{%s,%zu,%zu},%d",
+	       call->type->name, call->iov_len, iov_iter_count(iter), want_more);
+
+	ret = rxrpc_kernel_recv_data(net->socket, call->rxcall, iter,
+				     &call->iov_len, want_more, &remote_abort,
+				     &call->service_id);
+	trace_afs_receive_data(call, call->iter, want_more, ret);
+	if (ret == 0 || ret == -EAGAIN)
+		return ret;
+
+	state = READ_ONCE(call->state);
+	if (ret == 1) {
+		switch (state) {
+		case AFS_CALL_CL_AWAIT_REPLY:
+			afs_set_call_state(call, state, AFS_CALL_CL_PROC_REPLY);
+			break;
+		case AFS_CALL_SV_AWAIT_REQUEST:
+			afs_set_call_state(call, state, AFS_CALL_SV_REPLYING);
+			break;
+		case AFS_CALL_COMPLETE:
+			kdebug("prem complete %d", call->error);
+			return afs_io_error(call, afs_io_error_extract);
+		default:
+			break;
+		}
+		return 0;
+	}
+
+	afs_set_call_complete(call, ret, remote_abort);
+	return ret;
+}
+
+/*
+ * Log protocol error production.
+ */
+noinline int afs_protocol_error(struct afs_call *call,
+				enum afs_eproto_cause cause)
+{
+	trace_afs_protocol_error(call, cause);
+	if (call)
+		call->unmarshalling_error = true;
+	return -EBADMSG;
+}