atm_misc.c
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/* net/atm/atm_misc.c - Various functions for use by ATM drivers */
/* Written 1995-2000 by Werner Almesberger, EPFL ICA */
#include <linux/module.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/skbuff.h>
#include <linux/sonet.h>
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/atomic.h>
int atm_charge(struct atm_vcc *vcc, int truesize)
{
atm_force_charge(vcc, truesize);
if (atomic_read(&sk_atm(vcc)->sk_rmem_alloc) <= sk_atm(vcc)->sk_rcvbuf)
return 1;
atm_return(vcc, truesize);
atomic_inc(&vcc->stats->rx_drop);
return 0;
}
EXPORT_SYMBOL(atm_charge);
struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc, int pdu_size,
gfp_t gfp_flags)
{
struct sock *sk = sk_atm(vcc);
int guess = SKB_TRUESIZE(pdu_size);
atm_force_charge(vcc, guess);
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) {
struct sk_buff *skb = alloc_skb(pdu_size, gfp_flags);
if (skb) {
atomic_add(skb->truesize-guess,
&sk->sk_rmem_alloc);
return skb;
}
}
atm_return(vcc, guess);
atomic_inc(&vcc->stats->rx_drop);
return NULL;
}
EXPORT_SYMBOL(atm_alloc_charge);
/*
* 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(const 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_pcr_goal);
void sonet_copy_stats(struct k_sonet_stats *from, struct sonet_stats *to)
{
#define __HANDLE_ITEM(i) to->i = atomic_read(&from->i)
__SONET_ITEMS
#undef __HANDLE_ITEM
}
EXPORT_SYMBOL(sonet_copy_stats);
void sonet_subtract_stats(struct k_sonet_stats *from, struct sonet_stats *to)
{
#define __HANDLE_ITEM(i) atomic_sub(to->i, &from->i)
__SONET_ITEMS
#undef __HANDLE_ITEM
}
EXPORT_SYMBOL(sonet_subtract_stats);