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/* net/atm/atm_misc.c - Various functions for use by ATM drivers */
/* Written 1995-1999 by Werner Almesberger, EPFL ICA */
#include <linux/module.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/skbuff.h>
#include <asm/atomic.h>
#include <asm/errno.h>
int atm_charge(struct atm_vcc *vcc,int truesize)
{
atm_force_charge(vcc,truesize);
if (atomic_read(&vcc->rx_inuse) <= vcc->sk->rcvbuf) return 1;
atm_return(vcc,truesize);
vcc->stats->rx_drop++;
return 0;
}
struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc,int pdu_size,
int gfp_flags)
{
int guess = atm_guess_pdu2truesize(pdu_size);
atm_force_charge(vcc,guess);
if (atomic_read(&vcc->rx_inuse) <= vcc->sk->rcvbuf) {
struct sk_buff *skb = alloc_skb(pdu_size,gfp_flags);
if (skb) {
atomic_add(skb->truesize-guess,&vcc->rx_inuse);
return skb;
}
}
atm_return(vcc,guess);
vcc->stats->rx_drop++;
return NULL;
}
static int check_ci(struct atm_vcc *vcc,short vpi,int vci)
{
struct atm_vcc *walk;
for (walk = vcc->dev->vccs; walk; walk = walk->next)
if ((walk->flags & ATM_VF_ADDR) && walk->vpi == vpi &&
walk->vci == vci && ((walk->qos.txtp.traffic_class !=
ATM_NONE && vcc->qos.txtp.traffic_class != ATM_NONE) ||
(walk->qos.rxtp.traffic_class != ATM_NONE &&
vcc->qos.rxtp.traffic_class != ATM_NONE)))
return -EADDRINUSE;
/* allow VCCs with same VPI/VCI iff they don't collide on
TX/RX (but we may refuse such sharing for other reasons,
e.g. if protocol requires to have both channels) */
return 0;
}
int atm_find_ci(struct atm_vcc *vcc,short *vpi,int *vci)
{
static short p = 0; /* poor man's per-device cache */
static int c = 0;
short old_p;
int old_c;
if (*vpi != ATM_VPI_ANY && *vci != ATM_VCI_ANY)
return check_ci(vcc,*vpi,*vci);
/* last scan may have left values out of bounds for current device */
if (*vpi != ATM_VPI_ANY) p = *vpi;
else if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
if (*vci != ATM_VCI_ANY) c = *vci;
else if (c < ATM_NOT_RSV_VCI || c >= 1 << vcc->dev->ci_range.vci_bits)
c = ATM_NOT_RSV_VCI;
old_p = p;
old_c = c;
do {
if (!check_ci(vcc,p,c)) {
*vpi = p;
*vci = c;
return 0;
}
if (*vci == ATM_VCI_ANY) {
c++;
if (c >= 1 << vcc->dev->ci_range.vci_bits)
c = ATM_NOT_RSV_VCI;
}
if ((c == ATM_NOT_RSV_VCI || *vci != ATM_VCI_ANY) &&
*vpi == ATM_VPI_ANY) {
p++;
if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
}
}
while (old_p != p || old_c != c);
return -EADDRINUSE;
}
/*
* atm_pcr_goal returns the positive PCR if it should be rounded up, the
* negative PCR if it should be rounded down, and zero if the maximum available
* bandwidth should be used.
*
* The rules are as follows (* = maximum, - = absent (0), x = value "x",
* (x+ = x or next value above x, x- = x or next value below):
*
* min max pcr result min max pcr result
* - - - * (UBR only) x - - x+
* - - * * x - * *
* - - z z- x - z z-
* - * - * x * - x+
* - * * * x * * *
* - * z z- x * z z-
* - y - y- x y - x+
* - y * y- x y * y-
* - y z z- x y z z-
*
* All non-error cases can be converted with the following simple set of rules:
*
* if pcr == z then z-
* else if min == x && pcr == - then x+
* else if max == y then y-
* else *
*/
int atm_pcr_goal(struct atm_trafprm *tp)
{
if (tp->pcr && tp->pcr != ATM_MAX_PCR) return -tp->pcr;
if (tp->min_pcr && !tp->pcr) return tp->min_pcr;
if (tp->max_pcr != ATM_MAX_PCR) return -tp->max_pcr;
return 0;
}
EXPORT_SYMBOL(atm_charge);
EXPORT_SYMBOL(atm_alloc_charge);
EXPORT_SYMBOL(atm_find_ci);
EXPORT_SYMBOL(atm_pcr_goal);
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