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
16 int 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
27 struct 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
77 int 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
89 void 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
97 void 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
105 EXPORT_SYMBOL(atm_charge);
106 EXPORT_SYMBOL(atm_alloc_charge);
107 EXPORT_SYMBOL(atm_pcr_goal);
108 EXPORT_SYMBOL(sonet_copy_stats);
109 EXPORT_SYMBOL(sonet_subtract_stats);
110
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