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89b01913dc
In the case we trigger dlm_free_rsb() that does a call_rcu() and the
responding kfree() of res_lvbptr and a kmem_cache_free() of the rsb
pointer we need to wait until this pending operation is done before
calling kmem_cache_destroy(). We doing that by using rcu_barrier() that
waits until all pending call_rcu() are done. This avoids that
kmem_cache_destroy() complains about active objects around that are not
being freed yet by call_rcu().
There is currently more discussions about to make this behaviour better,
see:
https://lore.kernel.org/netdev/20240609082726.32742-1-Julia.Lawall@inria.fr/
However this is only for call_rcu() if the callback calls
kmem_cache_destroy() only to replace it by kfree_rcu() call which has
currently some issue. This isn't our case because we also free the
res_lvbptr if being set.
For our case, to avoid the above race rcu_barrier() should be used before
calling kmem_cache_destroy() to be sure that there are no active objects
around. This is exactly what net/batman-adv is also doing before calling their
kmem_cache_destroy() in module unloading.
Fixes: 01fdeca1cc ("dlm: use rcu to avoid an extra rsb struct lookup")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
180 lines
3.7 KiB
C
180 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/******************************************************************************
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*******************************************************************************
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**
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** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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** Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
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**
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**
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*******************************************************************************
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******************************************************************************/
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#include "dlm_internal.h"
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#include "midcomms.h"
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#include "lowcomms.h"
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#include "config.h"
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#include "memory.h"
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#include "ast.h"
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static struct kmem_cache *writequeue_cache;
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static struct kmem_cache *mhandle_cache;
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static struct kmem_cache *msg_cache;
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static struct kmem_cache *lkb_cache;
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static struct kmem_cache *rsb_cache;
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static struct kmem_cache *cb_cache;
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int __init dlm_memory_init(void)
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{
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writequeue_cache = dlm_lowcomms_writequeue_cache_create();
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if (!writequeue_cache)
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goto out;
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mhandle_cache = dlm_midcomms_cache_create();
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if (!mhandle_cache)
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goto mhandle;
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lkb_cache = kmem_cache_create("dlm_lkb", sizeof(struct dlm_lkb),
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__alignof__(struct dlm_lkb), 0, NULL);
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if (!lkb_cache)
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goto lkb;
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msg_cache = dlm_lowcomms_msg_cache_create();
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if (!msg_cache)
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goto msg;
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rsb_cache = kmem_cache_create("dlm_rsb", sizeof(struct dlm_rsb),
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__alignof__(struct dlm_rsb), 0, NULL);
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if (!rsb_cache)
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goto rsb;
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cb_cache = kmem_cache_create("dlm_cb", sizeof(struct dlm_callback),
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__alignof__(struct dlm_callback), 0,
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NULL);
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if (!cb_cache)
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goto cb;
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return 0;
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cb:
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kmem_cache_destroy(rsb_cache);
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rsb:
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kmem_cache_destroy(msg_cache);
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msg:
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kmem_cache_destroy(lkb_cache);
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lkb:
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kmem_cache_destroy(mhandle_cache);
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mhandle:
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kmem_cache_destroy(writequeue_cache);
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out:
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return -ENOMEM;
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}
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void dlm_memory_exit(void)
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{
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rcu_barrier();
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kmem_cache_destroy(writequeue_cache);
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kmem_cache_destroy(mhandle_cache);
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kmem_cache_destroy(msg_cache);
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kmem_cache_destroy(lkb_cache);
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kmem_cache_destroy(rsb_cache);
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kmem_cache_destroy(cb_cache);
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}
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char *dlm_allocate_lvb(struct dlm_ls *ls)
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{
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char *p;
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p = kzalloc(ls->ls_lvblen, GFP_ATOMIC);
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return p;
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}
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void dlm_free_lvb(char *p)
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{
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kfree(p);
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}
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struct dlm_rsb *dlm_allocate_rsb(struct dlm_ls *ls)
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{
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struct dlm_rsb *r;
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r = kmem_cache_zalloc(rsb_cache, GFP_ATOMIC);
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return r;
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}
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static void __free_rsb_rcu(struct rcu_head *rcu)
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{
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struct dlm_rsb *r = container_of(rcu, struct dlm_rsb, rcu);
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if (r->res_lvbptr)
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dlm_free_lvb(r->res_lvbptr);
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kmem_cache_free(rsb_cache, r);
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}
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void dlm_free_rsb(struct dlm_rsb *r)
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{
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call_rcu(&r->rcu, __free_rsb_rcu);
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}
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struct dlm_lkb *dlm_allocate_lkb(struct dlm_ls *ls)
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{
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struct dlm_lkb *lkb;
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lkb = kmem_cache_zalloc(lkb_cache, GFP_ATOMIC);
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return lkb;
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}
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void dlm_free_lkb(struct dlm_lkb *lkb)
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{
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if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
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struct dlm_user_args *ua;
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ua = lkb->lkb_ua;
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if (ua) {
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kfree(ua->lksb.sb_lvbptr);
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kfree(ua);
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}
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}
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kmem_cache_free(lkb_cache, lkb);
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}
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struct dlm_mhandle *dlm_allocate_mhandle(void)
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{
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return kmem_cache_alloc(mhandle_cache, GFP_ATOMIC);
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}
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void dlm_free_mhandle(struct dlm_mhandle *mhandle)
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{
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kmem_cache_free(mhandle_cache, mhandle);
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}
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struct writequeue_entry *dlm_allocate_writequeue(void)
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{
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return kmem_cache_alloc(writequeue_cache, GFP_ATOMIC);
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}
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void dlm_free_writequeue(struct writequeue_entry *writequeue)
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{
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kmem_cache_free(writequeue_cache, writequeue);
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}
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struct dlm_msg *dlm_allocate_msg(void)
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{
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return kmem_cache_alloc(msg_cache, GFP_ATOMIC);
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}
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void dlm_free_msg(struct dlm_msg *msg)
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{
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kmem_cache_free(msg_cache, msg);
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}
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struct dlm_callback *dlm_allocate_cb(void)
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{
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return kmem_cache_alloc(cb_cache, GFP_ATOMIC);
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}
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void dlm_free_cb(struct dlm_callback *cb)
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{
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kmem_cache_free(cb_cache, cb);
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}
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