1 /* net/atm/atm_misc.c - Various functions for use by ATM drivers */ 2 3 /* Written 1995-2000 by Werner Almesberger, EPFL ICA */ 4 5 #include <linux/module.h> 6 #include <linux/atm.h> 7 #include <linux/atmdev.h> 8 #include <linux/skbuff.h> 9 #include <linux/sonet.h> 10 #include <linux/bitops.h> 11 #include <linux/errno.h> 12 #include <linux/atomic.h> 13 14 int atm_charge(struct atm_vcc *vcc, int truesize) 15 { 16 atm_force_charge(vcc, truesize); 17 if (atomic_read(&sk_atm(vcc)->sk_rmem_alloc) <= sk_atm(vcc)->sk_rcvbuf) 18 return 1; 19 atm_return(vcc, truesize); 20 atomic_inc(&vcc->stats->rx_drop); 21 return 0; 22 } 23 EXPORT_SYMBOL(atm_charge); 24 25 struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc, int pdu_size, 26 gfp_t gfp_flags) 27 { 28 struct sock *sk = sk_atm(vcc); 29 int guess = atm_guess_pdu2truesize(pdu_size); 30 31 atm_force_charge(vcc, guess); 32 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) { 33 struct sk_buff *skb = alloc_skb(pdu_size, gfp_flags); 34 35 if (skb) { 36 atomic_add(skb->truesize-guess, 37 &sk->sk_rmem_alloc); 38 return skb; 39 } 40 } 41 atm_return(vcc, guess); 42 atomic_inc(&vcc->stats->rx_drop); 43 return NULL; 44 } 45 EXPORT_SYMBOL(atm_alloc_charge); 46 47 48 /* 49 * atm_pcr_goal returns the positive PCR if it should be rounded up, the 50 * negative PCR if it should be rounded down, and zero if the maximum available 51 * bandwidth should be used. 52 * 53 * The rules are as follows (* = maximum, - = absent (0), x = value "x", 54 * (x+ = x or next value above x, x- = x or next value below): 55 * 56 * min max pcr result min max pcr result 57 * - - - * (UBR only) x - - x+ 58 * - - * * x - * * 59 * - - z z- x - z z- 60 * - * - * x * - x+ 61 * - * * * x * * * 62 * - * z z- x * z z- 63 * - y - y- x y - x+ 64 * - y * y- x y * y- 65 * - y z z- x y z z- 66 * 67 * All non-error cases can be converted with the following simple set of rules: 68 * 69 * if pcr == z then z- 70 * else if min == x && pcr == - then x+ 71 * else if max == y then y- 72 * else * 73 */ 74 75 int atm_pcr_goal(const struct atm_trafprm *tp) 76 { 77 if (tp->pcr && tp->pcr != ATM_MAX_PCR) 78 return -tp->pcr; 79 if (tp->min_pcr && !tp->pcr) 80 return tp->min_pcr; 81 if (tp->max_pcr != ATM_MAX_PCR) 82 return -tp->max_pcr; 83 return 0; 84 } 85 EXPORT_SYMBOL(atm_pcr_goal); 86 87 void sonet_copy_stats(struct k_sonet_stats *from, struct sonet_stats *to) 88 { 89 #define __HANDLE_ITEM(i) to->i = atomic_read(&from->i) 90 __SONET_ITEMS 91 #undef __HANDLE_ITEM 92 } 93 EXPORT_SYMBOL(sonet_copy_stats); 94 95 void sonet_subtract_stats(struct k_sonet_stats *from, struct sonet_stats *to) 96 { 97 #define __HANDLE_ITEM(i) atomic_sub(to->i, &from->i) 98 __SONET_ITEMS 99 #undef __HANDLE_ITEM 100 } 101 EXPORT_SYMBOL(sonet_subtract_stats); 102