1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /* net/atm/atm_misc.c - Various functions for use by ATM drivers */
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun /* Written 1995-2000 by Werner Almesberger, EPFL ICA */
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #include <linux/module.h>
7*4882a593Smuzhiyun #include <linux/atm.h>
8*4882a593Smuzhiyun #include <linux/atmdev.h>
9*4882a593Smuzhiyun #include <linux/skbuff.h>
10*4882a593Smuzhiyun #include <linux/sonet.h>
11*4882a593Smuzhiyun #include <linux/bitops.h>
12*4882a593Smuzhiyun #include <linux/errno.h>
13*4882a593Smuzhiyun #include <linux/atomic.h>
14*4882a593Smuzhiyun
atm_charge(struct atm_vcc * vcc,int truesize)15*4882a593Smuzhiyun int atm_charge(struct atm_vcc *vcc, int truesize)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun atm_force_charge(vcc, truesize);
18*4882a593Smuzhiyun if (atomic_read(&sk_atm(vcc)->sk_rmem_alloc) <= sk_atm(vcc)->sk_rcvbuf)
19*4882a593Smuzhiyun return 1;
20*4882a593Smuzhiyun atm_return(vcc, truesize);
21*4882a593Smuzhiyun atomic_inc(&vcc->stats->rx_drop);
22*4882a593Smuzhiyun return 0;
23*4882a593Smuzhiyun }
24*4882a593Smuzhiyun EXPORT_SYMBOL(atm_charge);
25*4882a593Smuzhiyun
atm_alloc_charge(struct atm_vcc * vcc,int pdu_size,gfp_t gfp_flags)26*4882a593Smuzhiyun struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc, int pdu_size,
27*4882a593Smuzhiyun gfp_t gfp_flags)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun struct sock *sk = sk_atm(vcc);
30*4882a593Smuzhiyun int guess = SKB_TRUESIZE(pdu_size);
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun atm_force_charge(vcc, guess);
33*4882a593Smuzhiyun if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) {
34*4882a593Smuzhiyun struct sk_buff *skb = alloc_skb(pdu_size, gfp_flags);
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun if (skb) {
37*4882a593Smuzhiyun atomic_add(skb->truesize-guess,
38*4882a593Smuzhiyun &sk->sk_rmem_alloc);
39*4882a593Smuzhiyun return skb;
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun atm_return(vcc, guess);
43*4882a593Smuzhiyun atomic_inc(&vcc->stats->rx_drop);
44*4882a593Smuzhiyun return NULL;
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun EXPORT_SYMBOL(atm_alloc_charge);
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun /*
50*4882a593Smuzhiyun * atm_pcr_goal returns the positive PCR if it should be rounded up, the
51*4882a593Smuzhiyun * negative PCR if it should be rounded down, and zero if the maximum available
52*4882a593Smuzhiyun * bandwidth should be used.
53*4882a593Smuzhiyun *
54*4882a593Smuzhiyun * The rules are as follows (* = maximum, - = absent (0), x = value "x",
55*4882a593Smuzhiyun * (x+ = x or next value above x, x- = x or next value below):
56*4882a593Smuzhiyun *
57*4882a593Smuzhiyun * min max pcr result min max pcr result
58*4882a593Smuzhiyun * - - - * (UBR only) x - - x+
59*4882a593Smuzhiyun * - - * * x - * *
60*4882a593Smuzhiyun * - - z z- x - z z-
61*4882a593Smuzhiyun * - * - * x * - x+
62*4882a593Smuzhiyun * - * * * x * * *
63*4882a593Smuzhiyun * - * z z- x * z z-
64*4882a593Smuzhiyun * - y - y- x y - x+
65*4882a593Smuzhiyun * - y * y- x y * y-
66*4882a593Smuzhiyun * - y z z- x y z z-
67*4882a593Smuzhiyun *
68*4882a593Smuzhiyun * All non-error cases can be converted with the following simple set of rules:
69*4882a593Smuzhiyun *
70*4882a593Smuzhiyun * if pcr == z then z-
71*4882a593Smuzhiyun * else if min == x && pcr == - then x+
72*4882a593Smuzhiyun * else if max == y then y-
73*4882a593Smuzhiyun * else *
74*4882a593Smuzhiyun */
75*4882a593Smuzhiyun
atm_pcr_goal(const struct atm_trafprm * tp)76*4882a593Smuzhiyun int atm_pcr_goal(const struct atm_trafprm *tp)
77*4882a593Smuzhiyun {
78*4882a593Smuzhiyun if (tp->pcr && tp->pcr != ATM_MAX_PCR)
79*4882a593Smuzhiyun return -tp->pcr;
80*4882a593Smuzhiyun if (tp->min_pcr && !tp->pcr)
81*4882a593Smuzhiyun return tp->min_pcr;
82*4882a593Smuzhiyun if (tp->max_pcr != ATM_MAX_PCR)
83*4882a593Smuzhiyun return -tp->max_pcr;
84*4882a593Smuzhiyun return 0;
85*4882a593Smuzhiyun }
86*4882a593Smuzhiyun EXPORT_SYMBOL(atm_pcr_goal);
87*4882a593Smuzhiyun
sonet_copy_stats(struct k_sonet_stats * from,struct sonet_stats * to)88*4882a593Smuzhiyun void sonet_copy_stats(struct k_sonet_stats *from, struct sonet_stats *to)
89*4882a593Smuzhiyun {
90*4882a593Smuzhiyun #define __HANDLE_ITEM(i) to->i = atomic_read(&from->i)
91*4882a593Smuzhiyun __SONET_ITEMS
92*4882a593Smuzhiyun #undef __HANDLE_ITEM
93*4882a593Smuzhiyun }
94*4882a593Smuzhiyun EXPORT_SYMBOL(sonet_copy_stats);
95*4882a593Smuzhiyun
sonet_subtract_stats(struct k_sonet_stats * from,struct sonet_stats * to)96*4882a593Smuzhiyun void sonet_subtract_stats(struct k_sonet_stats *from, struct sonet_stats *to)
97*4882a593Smuzhiyun {
98*4882a593Smuzhiyun #define __HANDLE_ITEM(i) atomic_sub(to->i, &from->i)
99*4882a593Smuzhiyun __SONET_ITEMS
100*4882a593Smuzhiyun #undef __HANDLE_ITEM
101*4882a593Smuzhiyun }
102*4882a593Smuzhiyun EXPORT_SYMBOL(sonet_subtract_stats);
103