[linux-2.6-block.git] / net / rxrpc / skbuff.c

/* ar-skbuff.c: socket buffer destruction handling
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

/*
 * set up for the ACK at the end of the receive phase when we discard the final
 * receive phase data packet
 * - called with softirqs disabled
 */
static void rxrpc_request_final_ACK(struct rxrpc_call *call)
{
	/* the call may be aborted before we have a chance to ACK it */
	write_lock(&call->state_lock);

	switch (call->state) {
	case RXRPC_CALL_CLIENT_RECV_REPLY:
		call->state = RXRPC_CALL_CLIENT_FINAL_ACK;
		_debug("request final ACK");

		/* get an extra ref on the call for the final-ACK generator to
		 * release */
		rxrpc_get_call(call);
		set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
		if (try_to_del_timer_sync(&call->ack_timer) >= 0)
			rxrpc_queue_call(call);
		break;

	case RXRPC_CALL_SERVER_RECV_REQUEST:
		call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
	default:
		break;
	}

	write_unlock(&call->state_lock);
}

/*
 * drop the bottom ACK off of the call ACK window and advance the window
 */
static void rxrpc_hard_ACK_data(struct rxrpc_call *call,
				struct rxrpc_skb_priv *sp)
{
	int loop;
	u32 seq;

	spin_lock_bh(&call->lock);

	_debug("hard ACK #%u", sp->hdr.seq);

	for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
		call->ackr_window[loop] >>= 1;
		call->ackr_window[loop] |=
			call->ackr_window[loop + 1] << (BITS_PER_LONG - 1);
	}

	seq = sp->hdr.seq;
	ASSERTCMP(seq, ==, call->rx_data_eaten + 1);
	call->rx_data_eaten = seq;

	if (call->ackr_win_top < UINT_MAX)
		call->ackr_win_top++;

	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
		    call->rx_data_post, >=, call->rx_data_recv);
	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
		    call->rx_data_recv, >=, call->rx_data_eaten);

	if (sp->hdr.flags & RXRPC_LAST_PACKET) {
		rxrpc_request_final_ACK(call);
	} else if (atomic_dec_and_test(&call->ackr_not_idle) &&
		   test_and_clear_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags)) {
		/* We previously soft-ACK'd some received packets that have now
		 * been consumed, so send a hard-ACK if no more packets are
		 * immediately forthcoming to allow the transmitter to free up
		 * its Tx bufferage.
		 */
		_debug("send Rx idle ACK");
		__rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, sp->hdr.serial,
				    false);
	}

	spin_unlock_bh(&call->lock);
}

/*
 * destroy a packet that has an RxRPC control buffer
 * - advance the hard-ACK state of the parent call (done here in case something
 *   in the kernel bypasses recvmsg() and steals the packet directly off of the
 *   socket receive queue)
 */
void rxrpc_packet_destructor(struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	struct rxrpc_call *call = sp->call;

	_enter("%p{%p}", skb, call);

	if (call) {
		/* send the final ACK on a client call */
		if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
			rxrpc_hard_ACK_data(call, sp);
		rxrpc_put_call(call);
		sp->call = NULL;
	}

	if (skb->sk)
		sock_rfree(skb);
	_leave("");
}

/**
 * rxrpc_kernel_free_skb - Free an RxRPC socket buffer
 * @skb: The socket buffer to be freed
 *
 * Let RxRPC free its own socket buffer, permitting it to maintain debug
 * accounting.
 */
void rxrpc_kernel_free_skb(struct sk_buff *skb)
{
	rxrpc_free_skb(skb);
}
EXPORT_SYMBOL(rxrpc_kernel_free_skb);
Commit	Line	Data
17926a79 DH	1	/* ar-skbuff.c: socket buffer destruction handling
	2	*
	3	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
9b6d5398 JP	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9b6d5398 JP	13
17926a79 DH	14	#include <linux/module.h>
	15	#include <linux/net.h>
	16	#include <linux/skbuff.h>
	17	#include <net/sock.h>
	18	#include <net/af_rxrpc.h>
	19	#include "ar-internal.h"
	20
	21	/*
	22	* set up for the ACK at the end of the receive phase when we discard the final
	23	* receive phase data packet
	24	* - called with softirqs disabled
	25	*/
	26	static void rxrpc_request_final_ACK(struct rxrpc_call *call)
	27	{
	28	/* the call may be aborted before we have a chance to ACK it */
	29	write_lock(&call->state_lock);
	30
	31	switch (call->state) {
	32	case RXRPC_CALL_CLIENT_RECV_REPLY:
	33	call->state = RXRPC_CALL_CLIENT_FINAL_ACK;
	34	_debug("request final ACK");
	35
	36	/* get an extra ref on the call for the final-ACK generator to
	37	* release */
	38	rxrpc_get_call(call);
4c198ad1	39	set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
17926a79	40	if (try_to_del_timer_sync(&call->ack_timer) >= 0)
651350d1	41	rxrpc_queue_call(call);
17926a79 DH	42	break;
	43
	44	case RXRPC_CALL_SERVER_RECV_REQUEST:
	45	call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
	46	default:
	47	break;
	48	}
	49
	50	write_unlock(&call->state_lock);
	51	}
	52
	53	/*
	54	* drop the bottom ACK off of the call ACK window and advance the window
	55	*/
	56	static void rxrpc_hard_ACK_data(struct rxrpc_call *call,
	57	struct rxrpc_skb_priv *sp)
	58	{
	59	int loop;
	60	u32 seq;
	61
	62	spin_lock_bh(&call->lock);
	63
0d12f8a4	64	_debug("hard ACK #%u", sp->hdr.seq);
17926a79 DH	65
	66	for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
	67	call->ackr_window[loop] >>= 1;
	68	call->ackr_window[loop] \|=
	69	call->ackr_window[loop + 1] << (BITS_PER_LONG - 1);
	70	}
	71
0d12f8a4	72	seq = sp->hdr.seq;
17926a79 DH	73	ASSERTCMP(seq, ==, call->rx_data_eaten + 1);
	74	call->rx_data_eaten = seq;
	75
	76	if (call->ackr_win_top < UINT_MAX)
	77	call->ackr_win_top++;
	78
	79	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
	80	call->rx_data_post, >=, call->rx_data_recv);
	81	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
	82	call->rx_data_recv, >=, call->rx_data_eaten);
	83
	84	if (sp->hdr.flags & RXRPC_LAST_PACKET) {
	85	rxrpc_request_final_ACK(call);
	86	} else if (atomic_dec_and_test(&call->ackr_not_idle) &&
	87	test_and_clear_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags)) {
5873c083 DH	88	/* We previously soft-ACK'd some received packets that have now
	89	* been consumed, so send a hard-ACK if no more packets are
	90	* immediately forthcoming to allow the transmitter to free up
	91	* its Tx bufferage.
	92	*/
17926a79 DH	93	_debug("send Rx idle ACK");
17926a79 DH	94	__rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, sp->hdr.serial,
9823f39a	95	false);
17926a79 DH	96	}
	97
	98	spin_unlock_bh(&call->lock);
	99	}
	100
	101	/*
	102	* destroy a packet that has an RxRPC control buffer
	103	* - advance the hard-ACK state of the parent call (done here in case something
	104	* in the kernel bypasses recvmsg() and steals the packet directly off of the
	105	* socket receive queue)
	106	*/
	107	void rxrpc_packet_destructor(struct sk_buff *skb)
	108	{
	109	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	110	struct rxrpc_call *call = sp->call;
	111
	112	_enter("%p{%p}", skb, call);
	113
	114	if (call) {
	115	/* send the final ACK on a client call */
	116	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
	117	rxrpc_hard_ACK_data(call, sp);
	118	rxrpc_put_call(call);
	119	sp->call = NULL;
	120	}
	121
	122	if (skb->sk)
	123	sock_rfree(skb);
	124	_leave("");
	125	}
651350d1 DH	126
	127	/**
	128	* rxrpc_kernel_free_skb - Free an RxRPC socket buffer
	129	* @skb: The socket buffer to be freed
	130	*
	131	* Let RxRPC free its own socket buffer, permitting it to maintain debug
	132	* accounting.
	133	*/
	134	void rxrpc_kernel_free_skb(struct sk_buff *skb)
	135	{
	136	rxrpc_free_skb(skb);
	137	}
651350d1	138	EXPORT_SYMBOL(rxrpc_kernel_free_skb);