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/*-
* Copyright (c) 2017 Mellanox Technologies, Ltd.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include <linux/kernel.h>
#include <linux/irq_work.h>
#include <linux/llist.h>
#include <sys/param.h>
#include <sys/taskqueue.h>
#include <vm/uma.h>
struct linux_kmem_rcu {
struct rcu_head rcu_head;
struct linux_kmem_cache *cache;
};
struct linux_kmem_cache {
uma_zone_t cache_zone;
linux_kmem_ctor_t *cache_ctor;
unsigned cache_flags;
unsigned cache_size;
struct llist_head cache_items;
struct task cache_task;
};
#define LINUX_KMEM_TO_RCU(c, m) \
((struct linux_kmem_rcu *)((char *)(m) + \
(c)->cache_size - sizeof(struct linux_kmem_rcu)))
#define LINUX_RCU_TO_KMEM(r) \
((void *)((char *)(r) + sizeof(struct linux_kmem_rcu) - \
(r)->cache->cache_size))
static LLIST_HEAD(linux_kfree_async_list);
static void lkpi_kmem_cache_free_async_fn(void *, int);
void *
lkpi_kmem_cache_alloc(struct linux_kmem_cache *c, gfp_t flags)
{
return (uma_zalloc_arg(c->cache_zone, c,
linux_check_m_flags(flags)));
}
void *
lkpi_kmem_cache_zalloc(struct linux_kmem_cache *c, gfp_t flags)
{
return (uma_zalloc_arg(c->cache_zone, c,
linux_check_m_flags(flags | M_ZERO)));
}
static int
linux_kmem_ctor(void *mem, int size, void *arg, int flags)
{
struct linux_kmem_cache *c = arg;
if (unlikely(c->cache_flags & SLAB_TYPESAFE_BY_RCU)) {
struct linux_kmem_rcu *rcu = LINUX_KMEM_TO_RCU(c, mem);
/* duplicate cache pointer */
rcu->cache = c;
}
/* check for constructor */
if (likely(c->cache_ctor != NULL))
c->cache_ctor(mem);
return (0);
}
static void
linux_kmem_cache_free_rcu_callback(struct rcu_head *head)
{
struct linux_kmem_rcu *rcu =
container_of(head, struct linux_kmem_rcu, rcu_head);
uma_zfree(rcu->cache->cache_zone, LINUX_RCU_TO_KMEM(rcu));
}
struct linux_kmem_cache *
linux_kmem_cache_create(const char *name, size_t size, size_t align,
unsigned flags, linux_kmem_ctor_t *ctor)
{
struct linux_kmem_cache *c;
c = malloc(sizeof(*c), M_KMALLOC, M_WAITOK);
if (flags & SLAB_HWCACHE_ALIGN)
align = UMA_ALIGN_CACHE;
else if (align != 0)
align--;
if (flags & SLAB_TYPESAFE_BY_RCU) {
/* make room for RCU structure */
size = ALIGN(size, sizeof(void *));
size += sizeof(struct linux_kmem_rcu);
/* create cache_zone */
c->cache_zone = uma_zcreate(name, size,
linux_kmem_ctor, NULL, NULL, NULL,
align, UMA_ZONE_ZINIT);
} else {
/* make room for async task list items */
size = MAX(size, sizeof(struct llist_node));
/* create cache_zone */
c->cache_zone = uma_zcreate(name, size,
ctor ? linux_kmem_ctor : NULL, NULL,
NULL, NULL, align, 0);
}
c->cache_flags = flags;
c->cache_ctor = ctor;
c->cache_size = size;
init_llist_head(&c->cache_items);
TASK_INIT(&c->cache_task, 0, lkpi_kmem_cache_free_async_fn, c);
return (c);
}
static inline void
lkpi_kmem_cache_free_rcu(struct linux_kmem_cache *c, void *m)
{
struct linux_kmem_rcu *rcu = LINUX_KMEM_TO_RCU(c, m);
call_rcu(&rcu->rcu_head, linux_kmem_cache_free_rcu_callback);
}
static inline void
lkpi_kmem_cache_free_sync(struct linux_kmem_cache *c, void *m)
{
uma_zfree(c->cache_zone, m);
}
static void
lkpi_kmem_cache_free_async_fn(void *context, int pending)
{
struct linux_kmem_cache *c = context;
struct llist_node *freed, *next;
llist_for_each_safe(freed, next, llist_del_all(&c->cache_items))
lkpi_kmem_cache_free_sync(c, freed);
}
static inline void
lkpi_kmem_cache_free_async(struct linux_kmem_cache *c, void *m)
{
if (m == NULL)
return;
llist_add(m, &c->cache_items);
taskqueue_enqueue(linux_irq_work_tq, &c->cache_task);
}
void
lkpi_kmem_cache_free(struct linux_kmem_cache *c, void *m)
{
if (unlikely(c->cache_flags & SLAB_TYPESAFE_BY_RCU))
lkpi_kmem_cache_free_rcu(c, m);
else if (unlikely(curthread->td_critnest != 0))
lkpi_kmem_cache_free_async(c, m);
else
lkpi_kmem_cache_free_sync(c, m);
}
void
linux_kmem_cache_destroy(struct linux_kmem_cache *c)
{
if (c == NULL)
return;
if (unlikely(c->cache_flags & SLAB_TYPESAFE_BY_RCU)) {
/* make sure all free callbacks have been called */
rcu_barrier();
}
if (!llist_empty(&c->cache_items))
taskqueue_enqueue(linux_irq_work_tq, &c->cache_task);
taskqueue_drain(linux_irq_work_tq, &c->cache_task);
uma_zdestroy(c->cache_zone);
free(c, M_KMALLOC);
}
static void
linux_kfree_async_fn(void *context, int pending)
{
struct llist_node *freed;
while((freed = llist_del_first(&linux_kfree_async_list)) != NULL)
kfree(freed);
}
static struct task linux_kfree_async_task =
TASK_INITIALIZER(0, linux_kfree_async_fn, &linux_kfree_async_task);
void
linux_kfree_async(void *addr)
{
if (addr == NULL)
return;
llist_add(addr, &linux_kfree_async_list);
taskqueue_enqueue(linux_irq_work_tq, &linux_kfree_async_task);
}
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