rxrpc.c

linux 内核源代码

	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) {
			rxrpc_kernel_end_call(call->rxcall);
			call->rxcall = NULL;
			call->type->destructor(call);
			afs_free_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");
	rxrpc_kernel_end_call(call->rxcall);
	call->rxcall = NULL;
	call->type->destructor(call);
	afs_free_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 work_struct *work)
{
	struct afs_call *call =
		container_of(work, struct afs_call, async_work);

	_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 work_struct *work)
{
	struct afs_call *call =
		container_of(work, struct afs_call, async_work);

	_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 */
		rxrpc_kernel_end_call(call->rxcall);
		call->rxcall = NULL;
		if (call->type->destructor)
			call->type->destructor(call);

		/* we can't just delete the call because the work item may be
		 * queued */
		PREPARE_WORK(&call->async_work, 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;
			}

			INIT_WORK(&call->async_work, afs_process_async_call);
			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;
	struct iovec iov[1];

	_enter("");

	iov[0].iov_base		= NULL;
	iov[0].iov_len		= 0;
	msg.msg_name		= NULL;
	msg.msg_namelen		= 0;
	msg.msg_iov		= iov;
	msg.msg_iovlen		= 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:
		rxrpc_kernel_end_call(call->rxcall);
		call->rxcall = NULL;
		call->type->destructor(call);
		afs_free_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 iovec iov[1];
	int n;

	_enter("");

	iov[0].iov_base		= (void *) buf;
	iov[0].iov_len		= len;
	msg.msg_name		= NULL;
	msg.msg_namelen		= 0;
	msg.msg_iov		= iov;
	msg.msg_iovlen		= 1;
	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) {
		_leave(" [replied]");
		return;
	}
	if (n == -ENOMEM) {
		_debug("oom");
		rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
	}
	rxrpc_kernel_end_call(call->rxcall);
	call->rxcall = NULL;
	call->type->destructor(call);
	afs_free_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;
}