Arnaldo Carvalho de Melo | 77d8bf9 | 2005-08-09 20:00:51 -0700 | [diff] [blame] | 1 | /* |
| 2 | * INET An implementation of the TCP/IP protocol suite for the LINUX |
| 3 | * operating system. INET is implemented using the BSD Socket |
| 4 | * interface as the means of communication with the user level. |
| 5 | * |
| 6 | * Generic INET transport hashtables |
| 7 | * |
| 8 | * Authors: Lotsa people, from code originally in tcp |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or |
| 11 | * modify it under the terms of the GNU General Public License |
| 12 | * as published by the Free Software Foundation; either version |
| 13 | * 2 of the License, or (at your option) any later version. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/config.h> |
Arnaldo Carvalho de Melo | 2d8c4ce | 2005-08-09 20:07:13 -0700 | [diff] [blame] | 17 | #include <linux/module.h> |
Arnaldo Carvalho de Melo | f3f05f7 | 2005-08-09 20:08:09 -0700 | [diff] [blame^] | 18 | #include <linux/sched.h> |
Arnaldo Carvalho de Melo | 77d8bf9 | 2005-08-09 20:00:51 -0700 | [diff] [blame] | 19 | #include <linux/slab.h> |
Arnaldo Carvalho de Melo | f3f05f7 | 2005-08-09 20:08:09 -0700 | [diff] [blame^] | 20 | #include <linux/wait.h> |
Arnaldo Carvalho de Melo | 77d8bf9 | 2005-08-09 20:00:51 -0700 | [diff] [blame] | 21 | |
| 22 | #include <net/inet_hashtables.h> |
| 23 | |
| 24 | /* |
| 25 | * Allocate and initialize a new local port bind bucket. |
| 26 | * The bindhash mutex for snum's hash chain must be held here. |
| 27 | */ |
| 28 | struct inet_bind_bucket *inet_bind_bucket_create(kmem_cache_t *cachep, |
| 29 | struct inet_bind_hashbucket *head, |
| 30 | const unsigned short snum) |
| 31 | { |
| 32 | struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, SLAB_ATOMIC); |
| 33 | |
| 34 | if (tb != NULL) { |
| 35 | tb->port = snum; |
| 36 | tb->fastreuse = 0; |
| 37 | INIT_HLIST_HEAD(&tb->owners); |
| 38 | hlist_add_head(&tb->node, &head->chain); |
| 39 | } |
| 40 | return tb; |
| 41 | } |
| 42 | |
| 43 | EXPORT_SYMBOL(inet_bind_bucket_create); |
| 44 | |
| 45 | /* |
| 46 | * Caller must hold hashbucket lock for this tb with local BH disabled |
| 47 | */ |
| 48 | void inet_bind_bucket_destroy(kmem_cache_t *cachep, struct inet_bind_bucket *tb) |
| 49 | { |
| 50 | if (hlist_empty(&tb->owners)) { |
| 51 | __hlist_del(&tb->node); |
| 52 | kmem_cache_free(cachep, tb); |
| 53 | } |
| 54 | } |
Arnaldo Carvalho de Melo | 2d8c4ce | 2005-08-09 20:07:13 -0700 | [diff] [blame] | 55 | |
| 56 | void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, |
| 57 | const unsigned short snum) |
| 58 | { |
| 59 | struct inet_sock *inet = inet_sk(sk); |
| 60 | inet->num = snum; |
| 61 | sk_add_bind_node(sk, &tb->owners); |
| 62 | inet->bind_hash = tb; |
| 63 | } |
| 64 | |
| 65 | EXPORT_SYMBOL(inet_bind_hash); |
| 66 | |
| 67 | /* |
| 68 | * Get rid of any references to a local port held by the given sock. |
| 69 | */ |
| 70 | static void __inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk) |
| 71 | { |
| 72 | struct inet_sock *inet = inet_sk(sk); |
| 73 | const int bhash = inet_bhashfn(inet->num, hashinfo->bhash_size); |
| 74 | struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash]; |
| 75 | struct inet_bind_bucket *tb; |
| 76 | |
| 77 | spin_lock(&head->lock); |
| 78 | tb = inet->bind_hash; |
| 79 | __sk_del_bind_node(sk); |
| 80 | inet->bind_hash = NULL; |
| 81 | inet->num = 0; |
| 82 | inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); |
| 83 | spin_unlock(&head->lock); |
| 84 | } |
| 85 | |
| 86 | void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk) |
| 87 | { |
| 88 | local_bh_disable(); |
| 89 | __inet_put_port(hashinfo, sk); |
| 90 | local_bh_enable(); |
| 91 | } |
| 92 | |
| 93 | EXPORT_SYMBOL(inet_put_port); |
Arnaldo Carvalho de Melo | f3f05f7 | 2005-08-09 20:08:09 -0700 | [diff] [blame^] | 94 | |
| 95 | /* |
| 96 | * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP. |
| 97 | * Look, when several writers sleep and reader wakes them up, all but one |
| 98 | * immediately hit write lock and grab all the cpus. Exclusive sleep solves |
| 99 | * this, _but_ remember, it adds useless work on UP machines (wake up each |
| 100 | * exclusive lock release). It should be ifdefed really. |
| 101 | */ |
| 102 | void inet_listen_wlock(struct inet_hashinfo *hashinfo) |
| 103 | { |
| 104 | write_lock(&hashinfo->lhash_lock); |
| 105 | |
| 106 | if (atomic_read(&hashinfo->lhash_users)) { |
| 107 | DEFINE_WAIT(wait); |
| 108 | |
| 109 | for (;;) { |
| 110 | prepare_to_wait_exclusive(&hashinfo->lhash_wait, |
| 111 | &wait, TASK_UNINTERRUPTIBLE); |
| 112 | if (!atomic_read(&hashinfo->lhash_users)) |
| 113 | break; |
| 114 | write_unlock_bh(&hashinfo->lhash_lock); |
| 115 | schedule(); |
| 116 | write_lock_bh(&hashinfo->lhash_lock); |
| 117 | } |
| 118 | |
| 119 | finish_wait(&hashinfo->lhash_wait, &wait); |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | EXPORT_SYMBOL(inet_listen_wlock); |