path: root/net/rxrpc/sendmsg.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* AF_RXRPC sendmsg() implementation.
 *
 * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/net.h>
#include <linux/gfp.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include <linux/sched/signal.h>

#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"

/*
 * Propose an abort to be made in the I/O thread.
 */
bool rxrpc_propose_abort(struct rxrpc_call *call, s32 abort_code, int error,
			 enum rxrpc_abort_reason why)
{
	_enter("{%d},%d,%d,%u", call->debug_id, abort_code, error, why);

	if (!call->send_abort && !rxrpc_call_is_complete(call)) {
		call->send_abort_why = why;
		call->send_abort_err = error;
		call->send_abort_seq = 0;
		trace_rxrpc_abort_call(call, abort_code);
		/* Request abort locklessly vs rxrpc_input_call_event(). */
		smp_store_release(&call->send_abort, abort_code);
		rxrpc_poke_call(call, rxrpc_call_poke_abort);
		return true;
	}

	return false;
}

/*
 * Wait for a call to become connected.  Interruption here doesn't cause the
 * call to be aborted.
 */
static int rxrpc_wait_to_be_connected(struct rxrpc_call *call, long *timeo)
{
	DECLARE_WAITQUEUE(myself, current);
	int ret = 0;

	_enter("%d", call->debug_id);

	if (rxrpc_call_state(call) != RXRPC_CALL_CLIENT_AWAIT_CONN)
		goto no_wait;

	add_wait_queue_exclusive(&call->waitq, &myself);

	for (;;) {
		switch (call->interruptibility) {
		case RXRPC_INTERRUPTIBLE:
		case RXRPC_PREINTERRUPTIBLE:
			set_current_state(TASK_INTERRUPTIBLE);
			break;
		case RXRPC_UNINTERRUPTIBLE:
		default:
			set_current_state(TASK_UNINTERRUPTIBLE);
			break;
		}

		if (rxrpc_call_state(call) != RXRPC_CALL_CLIENT_AWAIT_CONN)
			break;
		if ((call->interruptibility == RXRPC_INTERRUPTIBLE ||
		     call->interruptibility == RXRPC_PREINTERRUPTIBLE) &&
		    signal_pending(current)) {
			ret = sock_intr_errno(*timeo);
			break;
		}
		*timeo = schedule_timeout(*timeo);
	}

	remove_wait_queue(&call->waitq, &myself);
	__set_current_state(TASK_RUNNING);

no_wait:
	if (ret == 0 && rxrpc_call_is_complete(call))
		ret = call->error;

	_leave(" = %d", ret);
	return ret;
}

/*
 * Return true if there's sufficient Tx queue space.
 */
static bool rxrpc_check_tx_space(struct rxrpc_call *call, rxrpc_seq_t *_tx_win)
{
	rxrpc_seq_t tx_bottom = READ_ONCE(call->tx_bottom);

	if (_tx_win)
		*_tx_win = tx_bottom;
	return call->send_top - tx_bottom < 256;
}

/*
 * Wait for space to appear in the Tx queue or a signal to occur.
 */
static int rxrpc_wait_for_tx_window_intr(struct rxrpc_sock *rx,
					 struct rxrpc_call *call,
					 long *timeo)
{
	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (rxrpc_check_tx_space(call, NULL))
			return 0;

		if (rxrpc_call_is_complete(call))
			return call->error;

		if (signal_pending(current))
			return sock_intr_errno(*timeo);

		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
		*timeo = schedule_timeout(*timeo);
	}
}

/*
 * Wait for space to appear in the Tx queue uninterruptibly, but with
 * a timeout of 2*RTT if no progress was made and a signal occurred.
 */
static int rxrpc_wait_for_tx_window_waitall(struct rxrpc_sock *rx,
					    struct rxrpc_call *call)
{
	rxrpc_seq_t tx_start, tx_win;
	signed long rtt, timeout;

	rtt = READ_ONCE(call->srtt_us) >> 3;
	rtt = usecs_to_jiffies(rtt) * 2;
	if (rtt < 2)
		rtt = 2;

	timeout = rtt;
	tx_start = READ_ONCE(call->tx_bottom);

	for (;;) {
		set_current_state(TASK_UNINTERRUPTIBLE);

		if (rxrpc_check_tx_space(call, &tx_win))
			return 0;

		if (rxrpc_call_is_complete(call))
			return call->error;

		if (timeout == 0 &&
		    tx_win == tx_start && signal_pending(current))
			return -EINTR;

		if (tx_win != tx_start) {
			timeout = rtt;
			tx_start = tx_win;
		}

		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
		timeout = schedule_timeout(timeout);
	}
}

/*
 * Wait for space to appear in the Tx queue uninterruptibly.
 */
static int rxrpc_wait_for_tx_window_nonintr(struct rxrpc_sock *rx,
					    struct rxrpc_call *call,
					    long *timeo)
{
	for (;;) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		if (rxrpc_check_tx_space(call, NULL))
			return 0;

		if (rxrpc_call_is_complete(call))
			return call->error;

		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
		*timeo = schedule_timeout(*timeo);
	}