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