1/* net/atm/atm_misc.c - Various functions for use by ATM drivers */
2
3/* Written 1995-2000 by Werner Almesberger, EPFL ICA */
4
5
6#include <linux/module.h>
7#include <linux/atm.h>
8#include <linux/atmdev.h>
9#include <linux/skbuff.h>
10#include <linux/sonet.h>
11#include <linux/bitops.h>
12#include <asm/atomic.h>
13#include <asm/errno.h>
14
15
16int atm_charge(struct atm_vcc *vcc,int truesize)
17{
18	atm_force_charge(vcc,truesize);
19	if (atomic_read(&sk_atm(vcc)->sk_rmem_alloc) <= sk_atm(vcc)->sk_rcvbuf)
20		return 1;
21	atm_return(vcc,truesize);
22	atomic_inc(&vcc->stats->rx_drop);
23	return 0;
24}
25
26
27struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc,int pdu_size,
28    gfp_t gfp_flags)
29{
30	struct sock *sk = sk_atm(vcc);
31	int guess = atm_guess_pdu2truesize(pdu_size);
32
33	atm_force_charge(vcc,guess);
34	if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) {
35		struct sk_buff *skb = alloc_skb(pdu_size,gfp_flags);
36
37		if (skb) {
38			atomic_add(skb->truesize-guess,
39				   &sk->sk_rmem_alloc);
40			return skb;
41		}
42	}
43	atm_return(vcc,guess);
44	atomic_inc(&vcc->stats->rx_drop);
45	return NULL;
46}
47
48
49/*
50 * atm_pcr_goal returns the positive PCR if it should be rounded up, the
51 * negative PCR if it should be rounded down, and zero if the maximum available
52 * bandwidth should be used.
53 *
54 * The rules are as follows (* = maximum, - = absent (0), x = value "x",
55 * (x+ = x or next value above x, x- = x or next value below):
56 *
57 *	min max pcr	result		min max pcr	result
58 *	-   -   -	* (UBR only)	x   -   -	x+
59 *	-   -   *	*		x   -   *	*
60 *	-   -   z	z-		x   -   z	z-
61 *	-   *   -	*		x   *   -	x+
62 *	-   *   *	*		x   *   *	*
63 *	-   *   z	z-		x   *   z	z-
64 *	-   y   -	y-		x   y   -	x+
65 *	-   y   *	y-		x   y   *	y-
66 *	-   y   z	z-		x   y   z	z-
67 *
68 * All non-error cases can be converted with the following simple set of rules:
69 *
70 *   if pcr == z then z-
71 *   else if min == x && pcr == - then x+
72 *     else if max == y then y-
73 *	 else *
74 */
75
76
77int atm_pcr_goal(const struct atm_trafprm *tp)
78{
79	if (tp->pcr && tp->pcr != ATM_MAX_PCR)
80		return -tp->pcr;
81	if (tp->min_pcr && !tp->pcr)
82		return tp->min_pcr;
83	if (tp->max_pcr != ATM_MAX_PCR)
84		return -tp->max_pcr;
85	return 0;
86}
87
88
89void sonet_copy_stats(struct k_sonet_stats *from,struct sonet_stats *to)
90{
91#define __HANDLE_ITEM(i) to->i = atomic_read(&from->i)
92	__SONET_ITEMS
93#undef __HANDLE_ITEM
94}
95
96
97void sonet_subtract_stats(struct k_sonet_stats *from,struct sonet_stats *to)
98{
99#define __HANDLE_ITEM(i) atomic_sub(to->i,&from->i)
100	__SONET_ITEMS
101#undef __HANDLE_ITEM
102}
103
104
105EXPORT_SYMBOL(atm_charge);
106EXPORT_SYMBOL(atm_alloc_charge);
107EXPORT_SYMBOL(atm_pcr_goal);
108EXPORT_SYMBOL(sonet_copy_stats);
109EXPORT_SYMBOL(sonet_subtract_stats);
110