forked from luck/tmp_suning_uos_patched
f3f05f7046
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
124 lines
3.3 KiB
C
124 lines
3.3 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Generic INET transport hashtables
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*
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* Authors: Lotsa people, from code originally in tcp
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/wait.h>
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#include <net/inet_hashtables.h>
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/*
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* Allocate and initialize a new local port bind bucket.
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* The bindhash mutex for snum's hash chain must be held here.
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*/
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struct inet_bind_bucket *inet_bind_bucket_create(kmem_cache_t *cachep,
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struct inet_bind_hashbucket *head,
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const unsigned short snum)
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{
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struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, SLAB_ATOMIC);
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if (tb != NULL) {
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tb->port = snum;
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tb->fastreuse = 0;
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INIT_HLIST_HEAD(&tb->owners);
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hlist_add_head(&tb->node, &head->chain);
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}
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return tb;
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}
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EXPORT_SYMBOL(inet_bind_bucket_create);
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/*
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* Caller must hold hashbucket lock for this tb with local BH disabled
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*/
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void inet_bind_bucket_destroy(kmem_cache_t *cachep, struct inet_bind_bucket *tb)
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{
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if (hlist_empty(&tb->owners)) {
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__hlist_del(&tb->node);
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kmem_cache_free(cachep, tb);
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}
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}
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void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
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const unsigned short snum)
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{
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struct inet_sock *inet = inet_sk(sk);
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inet->num = snum;
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sk_add_bind_node(sk, &tb->owners);
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inet->bind_hash = tb;
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}
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EXPORT_SYMBOL(inet_bind_hash);
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/*
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* Get rid of any references to a local port held by the given sock.
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*/
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static void __inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk)
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{
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struct inet_sock *inet = inet_sk(sk);
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const int bhash = inet_bhashfn(inet->num, hashinfo->bhash_size);
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struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
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struct inet_bind_bucket *tb;
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spin_lock(&head->lock);
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tb = inet->bind_hash;
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__sk_del_bind_node(sk);
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inet->bind_hash = NULL;
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inet->num = 0;
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inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
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spin_unlock(&head->lock);
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}
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void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk)
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{
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local_bh_disable();
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__inet_put_port(hashinfo, sk);
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local_bh_enable();
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}
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EXPORT_SYMBOL(inet_put_port);
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/*
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* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
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* Look, when several writers sleep and reader wakes them up, all but one
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* immediately hit write lock and grab all the cpus. Exclusive sleep solves
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* this, _but_ remember, it adds useless work on UP machines (wake up each
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* exclusive lock release). It should be ifdefed really.
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*/
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void inet_listen_wlock(struct inet_hashinfo *hashinfo)
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{
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write_lock(&hashinfo->lhash_lock);
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if (atomic_read(&hashinfo->lhash_users)) {
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DEFINE_WAIT(wait);
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for (;;) {
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prepare_to_wait_exclusive(&hashinfo->lhash_wait,
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&wait, TASK_UNINTERRUPTIBLE);
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if (!atomic_read(&hashinfo->lhash_users))
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break;
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write_unlock_bh(&hashinfo->lhash_lock);
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schedule();
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write_lock_bh(&hashinfo->lhash_lock);
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}
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finish_wait(&hashinfo->lhash_wait, &wait);
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}
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}
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EXPORT_SYMBOL(inet_listen_wlock);
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