LXR linux/net/atm/atm

   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
  15int 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}
  24EXPORT_SYMBOL(atm_charge);
  25
  26struct 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}
  46EXPORT_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
  76int 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}
  86EXPORT_SYMBOL(atm_pcr_goal);
  87
  88void 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}
  94EXPORT_SYMBOL(sonet_copy_stats);
  95
  96void 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}
 102EXPORT_SYMBOL(sonet_subtract_stats);
 103