1 // SPDX-License-Identifier: GPL-2.0
2 /* net/atm/atm_misc.c - Various functions for use by ATM drivers */
3 
4 /* Written 1995-2000 by Werner Almesberger, EPFL ICA */
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 <linux/errno.h>
13 #include <linux/atomic.h>
14 
atm_charge(struct atm_vcc * vcc,int truesize)15 int atm_charge(struct atm_vcc *vcc, int truesize)
16 {
17 	atm_force_charge(vcc, truesize);
18 	if (atomic_read(&sk_atm(vcc)->sk_rmem_alloc) <= sk_atm(vcc)->sk_rcvbuf)
19 		return 1;
20 	atm_return(vcc, truesize);
21 	atomic_inc(&vcc->stats->rx_drop);
22 	return 0;
23 }
24 EXPORT_SYMBOL(atm_charge);
25 
atm_alloc_charge(struct atm_vcc * vcc,int pdu_size,gfp_t gfp_flags)26 struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc, int pdu_size,
27 				 gfp_t gfp_flags)
28 {
29 	struct sock *sk = sk_atm(vcc);
30 	int guess = SKB_TRUESIZE(pdu_size);
31 
32 	atm_force_charge(vcc, guess);
33 	if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) {
34 		struct sk_buff *skb = alloc_skb(pdu_size, gfp_flags);
35 
36 		if (skb) {
37 			atomic_add(skb->truesize-guess,
38 				   &sk->sk_rmem_alloc);
39 			return skb;
40 		}
41 	}
42 	atm_return(vcc, guess);
43 	atomic_inc(&vcc->stats->rx_drop);
44 	return NULL;
45 }
46 EXPORT_SYMBOL(atm_alloc_charge);
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 
atm_pcr_goal(const struct atm_trafprm * tp)76 int atm_pcr_goal(const struct atm_trafprm *tp)
77 {
78 	if (tp->pcr && tp->pcr != ATM_MAX_PCR)
79 		return -tp->pcr;
80 	if (tp->min_pcr && !tp->pcr)
81 		return tp->min_pcr;
82 	if (tp->max_pcr != ATM_MAX_PCR)
83 		return -tp->max_pcr;
84 	return 0;
85 }
86 EXPORT_SYMBOL(atm_pcr_goal);
87 
sonet_copy_stats(struct k_sonet_stats * from,struct sonet_stats * to)88 void sonet_copy_stats(struct k_sonet_stats *from, struct sonet_stats *to)
89 {
90 #define __HANDLE_ITEM(i) to->i = atomic_read(&from->i)
91 	__SONET_ITEMS
92 #undef __HANDLE_ITEM
93 }
94 EXPORT_SYMBOL(sonet_copy_stats);
95 
sonet_subtract_stats(struct k_sonet_stats * from,struct sonet_stats * to)96 void sonet_subtract_stats(struct k_sonet_stats *from, struct sonet_stats *to)
97 {
98 #define __HANDLE_ITEM(i) atomic_sub(to->i, &from->i)
99 	__SONET_ITEMS
100 #undef __HANDLE_ITEM
101 }
102 EXPORT_SYMBOL(sonet_subtract_stats);
103