1 /* net/atm/atm_misc.c - Various functions for use by ATM drivers */
3 /* Written 1995-2000 by Werner Almesberger, EPFL ICA */
6 #include <linux/module.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>
16 int atm_charge(struct atm_vcc *vcc,int truesize)
18 atm_force_charge(vcc,truesize);
19 if (atomic_read(&vcc->sk->rmem_alloc) <= vcc->sk->rcvbuf) return 1;
20 atm_return(vcc,truesize);
21 atomic_inc(&vcc->stats->rx_drop);
26 struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc,int pdu_size,
29 int guess = atm_guess_pdu2truesize(pdu_size);
31 atm_force_charge(vcc,guess);
32 if (atomic_read(&vcc->sk->rmem_alloc) <= vcc->sk->rcvbuf) {
33 struct sk_buff *skb = alloc_skb(pdu_size,gfp_flags);
36 atomic_add(skb->truesize-guess,&vcc->sk->rmem_alloc);
40 atm_return(vcc,guess);
41 atomic_inc(&vcc->stats->rx_drop);
46 static int check_ci(struct atm_vcc *vcc,short vpi,int vci)
51 for (s = vcc_sklist; s; s = s->next) {
52 walk = s->protinfo.af_atm;
53 if (walk->dev != vcc->dev)
55 if (test_bit(ATM_VF_ADDR,&walk->flags) && walk->vpi == vpi &&
56 walk->vci == vci && ((walk->qos.txtp.traffic_class !=
57 ATM_NONE && vcc->qos.txtp.traffic_class != ATM_NONE) ||
58 (walk->qos.rxtp.traffic_class != ATM_NONE &&
59 vcc->qos.rxtp.traffic_class != ATM_NONE)))
62 /* allow VCCs with same VPI/VCI iff they don't collide on
63 TX/RX (but we may refuse such sharing for other reasons,
64 e.g. if protocol requires to have both channels) */
69 int atm_find_ci(struct atm_vcc *vcc,short *vpi,int *vci)
71 static short p = 0; /* poor man's per-device cache */
77 read_lock(&vcc_sklist_lock);
78 if (*vpi != ATM_VPI_ANY && *vci != ATM_VCI_ANY) {
79 err = check_ci(vcc,*vpi,*vci);
80 read_unlock(&vcc_sklist_lock);
83 /* last scan may have left values out of bounds for current device */
84 if (*vpi != ATM_VPI_ANY) p = *vpi;
85 else if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
86 if (*vci != ATM_VCI_ANY) c = *vci;
87 else if (c < ATM_NOT_RSV_VCI || c >= 1 << vcc->dev->ci_range.vci_bits)
92 if (!check_ci(vcc,p,c)) {
95 read_unlock(&vcc_sklist_lock);
98 if (*vci == ATM_VCI_ANY) {
100 if (c >= 1 << vcc->dev->ci_range.vci_bits)
103 if ((c == ATM_NOT_RSV_VCI || *vci != ATM_VCI_ANY) &&
104 *vpi == ATM_VPI_ANY) {
106 if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
109 while (old_p != p || old_c != c);
110 read_unlock(&vcc_sklist_lock);
116 * atm_pcr_goal returns the positive PCR if it should be rounded up, the
117 * negative PCR if it should be rounded down, and zero if the maximum available
118 * bandwidth should be used.
120 * The rules are as follows (* = maximum, - = absent (0), x = value "x",
121 * (x+ = x or next value above x, x- = x or next value below):
123 * min max pcr result min max pcr result
124 * - - - * (UBR only) x - - x+
134 * All non-error cases can be converted with the following simple set of rules:
136 * if pcr == z then z-
137 * else if min == x && pcr == - then x+
138 * else if max == y then y-
143 int atm_pcr_goal(struct atm_trafprm *tp)
145 if (tp->pcr && tp->pcr != ATM_MAX_PCR) return -tp->pcr;
146 if (tp->min_pcr && !tp->pcr) return tp->min_pcr;
147 if (tp->max_pcr != ATM_MAX_PCR) return -tp->max_pcr;
152 void sonet_copy_stats(struct k_sonet_stats *from,struct sonet_stats *to)
154 #define __HANDLE_ITEM(i) to->i = atomic_read(&from->i)
160 void sonet_subtract_stats(struct k_sonet_stats *from,struct sonet_stats *to)
162 #define __HANDLE_ITEM(i) atomic_sub(to->i,&from->i)
168 EXPORT_SYMBOL(atm_charge);
169 EXPORT_SYMBOL(atm_alloc_charge);
170 EXPORT_SYMBOL(atm_find_ci);
171 EXPORT_SYMBOL(atm_pcr_goal);
172 EXPORT_SYMBOL(sonet_copy_stats);
173 EXPORT_SYMBOL(sonet_subtract_stats);