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/*
* net/dccp/ccid.c
*
* An implementation of the DCCP protocol
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* CCID infrastructure
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include "ccid.h"
static struct ccid_operations *ccids[CCID_MAX];
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
static atomic_t ccids_lockct = ATOMIC_INIT(0);
static DEFINE_SPINLOCK(ccids_lock);
/*
* The strategy is: modifications ccids vector are short, do not sleep and
* veeery rare, but read access should be free of any exclusive locks.
*/
static void ccids_write_lock(void)
{
spin_lock(&ccids_lock);
while (atomic_read(&ccids_lockct) != 0) {
spin_unlock(&ccids_lock);
yield();
spin_lock(&ccids_lock);
}
}
static inline void ccids_write_unlock(void)
{
spin_unlock(&ccids_lock);
}
static inline void ccids_read_lock(void)
{
atomic_inc(&ccids_lockct);
smp_mb__after_atomic_inc();
spin_unlock_wait(&ccids_lock);
}
static inline void ccids_read_unlock(void)
{
atomic_dec(&ccids_lockct);
}
#else
#define ccids_write_lock() do { } while(0)
#define ccids_write_unlock() do { } while(0)
#define ccids_read_lock() do { } while(0)
#define ccids_read_unlock() do { } while(0)
#endif
static struct kmem_cache *ccid_kmem_cache_create(int obj_size, const char *fmt,...)
{
struct kmem_cache *slab;
char slab_name_fmt[32], *slab_name;
va_list args;
va_start(args, fmt);
vsnprintf(slab_name_fmt, sizeof(slab_name_fmt), fmt, args);
va_end(args);
slab_name = kstrdup(slab_name_fmt, GFP_KERNEL);
if (slab_name == NULL)
return NULL;
slab = kmem_cache_create(slab_name, sizeof(struct ccid) + obj_size, 0,
SLAB_HWCACHE_ALIGN, NULL);
if (slab == NULL)
kfree(slab_name);
return slab;
}
static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
{
if (slab != NULL) {
const char *name = kmem_cache_name(slab);
kmem_cache_destroy(slab);
kfree(name);
}
}
int ccid_register(struct ccid_operations *ccid_ops)
{
int err = -ENOBUFS;
ccid_ops->ccid_hc_rx_slab =
ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
"%s_hc_rx_sock",
ccid_ops->ccid_name);
if (ccid_ops->ccid_hc_rx_slab == NULL)
goto out;
ccid_ops->ccid_hc_tx_slab =
ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
"%s_hc_tx_sock",
ccid_ops->ccid_name);
if (ccid_ops->ccid_hc_tx_slab == NULL)
goto out_free_rx_slab;
ccids_write_lock();
err = -EEXIST;
if (ccids[ccid_ops->ccid_id] == NULL) {
ccids[ccid_ops->ccid_id] = ccid_ops;
err = 0;
}
ccids_write_unlock();
if (err != 0)
goto out_free_tx_slab;
pr_info("CCID: Registered CCID %d (%s)\n",
ccid_ops->ccid_id, ccid_ops->ccid_name);
out:
return err;
out_free_tx_slab:
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
ccid_ops->ccid_hc_tx_slab = NULL;
goto out;
out_free_rx_slab:
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
ccid_ops->ccid_hc_rx_slab = NULL;
goto out;
}
EXPORT_SYMBOL_GPL(ccid_register);
int ccid_unregister(struct ccid_operations *ccid_ops)
{
ccids_write_lock();
ccids[ccid_ops->ccid_id] = NULL;
ccids_write_unlock();
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
ccid_ops->ccid_hc_tx_slab = NULL;
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
ccid_ops->ccid_hc_rx_slab = NULL;
pr_info("CCID: Unregistered CCID %d (%s)\n",
ccid_ops->ccid_id, ccid_ops->ccid_name);
return 0;
}
EXPORT_SYMBOL_GPL(ccid_unregister);
struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp)
{
struct ccid_operations *ccid_ops;
struct ccid *ccid = NULL;
ccids_read_lock();
#ifdef CONFIG_KMOD
if (ccids[id] == NULL) {
/* We only try to load if in process context */
ccids_read_unlock();
if (gfp & GFP_ATOMIC)
goto out;
request_module("net-dccp-ccid-%d", id);
ccids_read_lock();
}
#endif
ccid_ops = ccids[id];
if (ccid_ops == NULL)
goto out_unlock;
if (!try_module_get(ccid_ops->ccid_owner))
goto out_unlock;
ccids_read_unlock();
ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
ccid_ops->ccid_hc_tx_slab, gfp);
if (ccid == NULL)
goto out_module_put;
ccid->ccid_ops = ccid_ops;
if (rx) {
memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
goto out_free_ccid;
} else {
memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
goto out_free_ccid;
}
out:
return ccid;
out_unlock:
ccids_read_unlock();
goto out;
out_free_ccid:
kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
ccid_ops->ccid_hc_tx_slab, ccid);
ccid = NULL;
out_module_put:
module_put(ccid_ops->ccid_owner);
goto out;
}
EXPORT_SYMBOL_GPL(ccid_new);
struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk, gfp_t gfp)
{
return ccid_new(id, sk, 1, gfp);
}
EXPORT_SYMBOL_GPL(ccid_hc_rx_new);
struct ccid *ccid_hc_tx_new(unsigned char id,struct sock *sk, gfp_t gfp)
{
return ccid_new(id, sk, 0, gfp);
}
EXPORT_SYMBOL_GPL(ccid_hc_tx_new);
static void ccid_delete(struct ccid *ccid, struct sock *sk, int rx)
{
struct ccid_operations *ccid_ops;
if (ccid == NULL)
return;
ccid_ops = ccid->ccid_ops;
if (rx) {
if (ccid_ops->ccid_hc_rx_exit != NULL)
ccid_ops->ccid_hc_rx_exit(sk);
kmem_cache_free(ccid_ops->ccid_hc_rx_slab, ccid);
} else {
if (ccid_ops->ccid_hc_tx_exit != NULL)
ccid_ops->ccid_hc_tx_exit(sk);
kmem_cache_free(ccid_ops->ccid_hc_tx_slab, ccid);
}
ccids_read_lock();
if (ccids[ccid_ops->ccid_id] != NULL)
module_put(ccid_ops->ccid_owner);
ccids_read_unlock();
}
void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
{
ccid_delete(ccid, sk, 1);
}
EXPORT_SYMBOL_GPL(ccid_hc_rx_delete);
void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
{
ccid_delete(ccid, sk, 0);
}
EXPORT_SYMBOL_GPL(ccid_hc_tx_delete);
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