linux/fs/dlm/memory.c
Alexander Aring c846f732b9 dlm: move lkb xarray lookup out of lock
This patch moves the xarray lookup functionality for the lkb out of the
ls_lkbxa_lock read lock handling. We can do that as the xarray should be
possible to access lockless in case of reader like xa_load(). We confirm
under ls_lkbxa_lock that the lkb is still part of the data structure and
take a reference when its still part of ls_lkbxa to avoid being freed
after doing the lookup. To do a check if the lkb is still part of the
ls_lkbxa data structure we use a kref_read() as the last put will remove
it from the ls_lkbxa data structure and any reference taken means it is
still part of ls_lkbxa.

A similar approach was done with the DLM rsb rhashtable just with a flag
instead of the refcounter because the refcounter has a slightly
different meaning.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
2024-08-08 15:15:08 -05:00

178 lines
3.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
**
**
*******************************************************************************
******************************************************************************/
#include "dlm_internal.h"
#include "midcomms.h"
#include "lowcomms.h"
#include "config.h"
#include "memory.h"
#include "ast.h"
static struct kmem_cache *writequeue_cache;
static struct kmem_cache *mhandle_cache;
static struct kmem_cache *msg_cache;
static struct kmem_cache *lkb_cache;
static struct kmem_cache *rsb_cache;
static struct kmem_cache *cb_cache;
int __init dlm_memory_init(void)
{
writequeue_cache = dlm_lowcomms_writequeue_cache_create();
if (!writequeue_cache)
goto out;
mhandle_cache = dlm_midcomms_cache_create();
if (!mhandle_cache)
goto mhandle;
lkb_cache = kmem_cache_create("dlm_lkb", sizeof(struct dlm_lkb),
__alignof__(struct dlm_lkb), 0, NULL);
if (!lkb_cache)
goto lkb;
msg_cache = dlm_lowcomms_msg_cache_create();
if (!msg_cache)
goto msg;
rsb_cache = kmem_cache_create("dlm_rsb", sizeof(struct dlm_rsb),
__alignof__(struct dlm_rsb), 0, NULL);
if (!rsb_cache)
goto rsb;
cb_cache = kmem_cache_create("dlm_cb", sizeof(struct dlm_callback),
__alignof__(struct dlm_callback), 0,
NULL);
if (!cb_cache)
goto cb;
return 0;
cb:
kmem_cache_destroy(rsb_cache);
rsb:
kmem_cache_destroy(msg_cache);
msg:
kmem_cache_destroy(lkb_cache);
lkb:
kmem_cache_destroy(mhandle_cache);
mhandle:
kmem_cache_destroy(writequeue_cache);
out:
return -ENOMEM;
}
void dlm_memory_exit(void)
{
rcu_barrier();
kmem_cache_destroy(writequeue_cache);
kmem_cache_destroy(mhandle_cache);
kmem_cache_destroy(msg_cache);
kmem_cache_destroy(lkb_cache);
kmem_cache_destroy(rsb_cache);
kmem_cache_destroy(cb_cache);
}
char *dlm_allocate_lvb(struct dlm_ls *ls)
{
return kzalloc(ls->ls_lvblen, GFP_ATOMIC);
}
void dlm_free_lvb(char *p)
{
kfree(p);
}
struct dlm_rsb *dlm_allocate_rsb(void)
{
return kmem_cache_zalloc(rsb_cache, GFP_ATOMIC);
}
static void __free_rsb_rcu(struct rcu_head *rcu)
{
struct dlm_rsb *r = container_of(rcu, struct dlm_rsb, rcu);
if (r->res_lvbptr)
dlm_free_lvb(r->res_lvbptr);
kmem_cache_free(rsb_cache, r);
}
void dlm_free_rsb(struct dlm_rsb *r)
{
call_rcu(&r->rcu, __free_rsb_rcu);
}
struct dlm_lkb *dlm_allocate_lkb(void)
{
return kmem_cache_zalloc(lkb_cache, GFP_ATOMIC);
}
static void __free_lkb_rcu(struct rcu_head *rcu)
{
struct dlm_lkb *lkb = container_of(rcu, struct dlm_lkb, rcu);
if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
struct dlm_user_args *ua;
ua = lkb->lkb_ua;
if (ua) {
kfree(ua->lksb.sb_lvbptr);
kfree(ua);
}
}
kmem_cache_free(lkb_cache, lkb);
}
void dlm_free_lkb(struct dlm_lkb *lkb)
{
call_rcu(&lkb->rcu, __free_lkb_rcu);
}
struct dlm_mhandle *dlm_allocate_mhandle(void)
{
return kmem_cache_alloc(mhandle_cache, GFP_ATOMIC);
}
void dlm_free_mhandle(struct dlm_mhandle *mhandle)
{
kmem_cache_free(mhandle_cache, mhandle);
}
struct writequeue_entry *dlm_allocate_writequeue(void)
{
return kmem_cache_alloc(writequeue_cache, GFP_ATOMIC);
}
void dlm_free_writequeue(struct writequeue_entry *writequeue)
{
kmem_cache_free(writequeue_cache, writequeue);
}
struct dlm_msg *dlm_allocate_msg(void)
{
return kmem_cache_alloc(msg_cache, GFP_ATOMIC);
}
void dlm_free_msg(struct dlm_msg *msg)
{
kmem_cache_free(msg_cache, msg);
}
struct dlm_callback *dlm_allocate_cb(void)
{
return kmem_cache_alloc(cb_cache, GFP_ATOMIC);
}
void dlm_free_cb(struct dlm_callback *cb)
{
kmem_cache_free(cb_cache, cb);
}