linux/fs/dlm/memory.c
Alexander Aring 8a39dcd9c3 fs: dlm: change dflags to use atomic bits
Currently manipulating lkb_dflags assumes to held the rsb lock assigned
to the lkb. This is held by dlm message processing after certain
time to lookup the right rsb from the received lkb message id. For user
space locks flags, which is currently the only use case for lkb_dflags,
flags are also being set during dlm character device handling without
holding the rsb lock. To minimize the risk that bit operations are
getting corrupted we switch to atomic bit operations. This patch will
also introduce helpers to snapshot atomic bit values in an non atomic
way. There might be still issues with the flag handling e.g. running in
case of manipulating bit ops and snapshot them at the same time, but this
patch minimize them and will start to use atomic bit operations.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
2023-03-06 15:49:07 -06:00

176 lines
3.7 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)
{
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)
{
char *p;
p = kzalloc(ls->ls_lvblen, GFP_NOFS);
return p;
}
void dlm_free_lvb(char *p)
{
kfree(p);
}
struct dlm_rsb *dlm_allocate_rsb(struct dlm_ls *ls)
{
struct dlm_rsb *r;
r = kmem_cache_zalloc(rsb_cache, GFP_NOFS);
return r;
}
void dlm_free_rsb(struct dlm_rsb *r)
{
if (r->res_lvbptr)
dlm_free_lvb(r->res_lvbptr);
kmem_cache_free(rsb_cache, r);
}
struct dlm_lkb *dlm_allocate_lkb(struct dlm_ls *ls)
{
struct dlm_lkb *lkb;
lkb = kmem_cache_zalloc(lkb_cache, GFP_NOFS);
return lkb;
}
void dlm_free_lkb(struct dlm_lkb *lkb)
{
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);
}
}
/* drop references if they are set */
dlm_callback_set_last_ptr(&lkb->lkb_last_cast, NULL);
dlm_callback_set_last_ptr(&lkb->lkb_last_cb, NULL);
kmem_cache_free(lkb_cache, lkb);
}
struct dlm_mhandle *dlm_allocate_mhandle(gfp_t allocation)
{
return kmem_cache_alloc(mhandle_cache, allocation);
}
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(gfp_t allocation)
{
return kmem_cache_alloc(msg_cache, allocation);
}
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);
}