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 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 <asm/atomic.h> 13 #include <asm/errno.h> 14 15 16 int atm_charge(struct atm_vcc *vcc,int truesize) 17 { 18 atm_force_charge(vcc,truesize); 19 if (atomic_read(&sk_atm(vcc)->sk_rmem_alloc) <= sk_atm(vcc)->sk_rcvbuf) 20 return 1; 21 atm_return(vcc,truesize); 22 atomic_inc(&vcc->stats->rx_drop); 23 return 0; 24 } 25 26 27 struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc,int pdu_size, 28 gfp_t gfp_flags) 29 { 30 struct sock *sk = sk_atm(vcc); 31 int guess = atm_guess_pdu2truesize(pdu_size); 32 33 atm_force_charge(vcc,guess); 34 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) { 35 struct sk_buff *skb = alloc_skb(pdu_size,gfp_flags); 36 37 if (skb) { 38 atomic_add(skb->truesize-guess, 39 &sk->sk_rmem_alloc); 40 return skb; 41 } 42 } 43 atm_return(vcc,guess); 44 atomic_inc(&vcc->stats->rx_drop); 45 return NULL; 46 } 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 76 77 int atm_pcr_goal(const struct atm_trafprm *tp) 78 { 79 if (tp->pcr && tp->pcr != ATM_MAX_PCR) 80 return -tp->pcr; 81 if (tp->min_pcr && !tp->pcr) 82 return tp->min_pcr; 83 if (tp->max_pcr != ATM_MAX_PCR) 84 return -tp->max_pcr; 85 return 0; 86 } 87 88 89 void sonet_copy_stats(struct k_sonet_stats *from,struct sonet_stats *to) 90 { 91 #define __HANDLE_ITEM(i) to->i = atomic_read(&from->i) 92 __SONET_ITEMS 93 #undef __HANDLE_ITEM 94 } 95 96 97 void sonet_subtract_stats(struct k_sonet_stats *from,struct sonet_stats *to) 98 { 99 #define __HANDLE_ITEM(i) atomic_sub(to->i,&from->i) 100 __SONET_ITEMS 101 #undef __HANDLE_ITEM 102 } 103 104 105 EXPORT_SYMBOL(atm_charge); 106 EXPORT_SYMBOL(atm_alloc_charge); 107 EXPORT_SYMBOL(atm_pcr_goal); 108 EXPORT_SYMBOL(sonet_copy_stats); 109 EXPORT_SYMBOL(sonet_subtract_stats); 110