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/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
**
** This copyrighted material is made available to anyone wishing to use,
** modify, copy, or redistribute it subject to the terms and conditions
** of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/
#include "dlm_internal.h"
#include "lock.h"
#include "user.h"
#include "ast.h"
#define WAKE_ASTS 0
static struct list_head ast_queue;
static spinlock_t ast_queue_lock;
static struct task_struct * astd_task;
static unsigned long astd_wakeflags;
static struct mutex astd_running;
void dlm_del_ast(struct dlm_lkb *lkb)
{
spin_lock(&ast_queue_lock);
if (lkb->lkb_ast_type & (AST_COMP | AST_BAST))
list_del(&lkb->lkb_astqueue);
spin_unlock(&ast_queue_lock);
}
void dlm_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
{
if (lkb->lkb_flags & DLM_IFL_USER) {
dlm_user_add_ast(lkb, type, bastmode);
return;
}
spin_lock(&ast_queue_lock);
if (!(lkb->lkb_ast_type & (AST_COMP | AST_BAST))) {
kref_get(&lkb->lkb_ref);
list_add_tail(&lkb->lkb_astqueue, &ast_queue);
}
lkb->lkb_ast_type |= type;
if (bastmode)
lkb->lkb_bastmode = bastmode;
spin_unlock(&ast_queue_lock);
set_bit(WAKE_ASTS, &astd_wakeflags);
wake_up_process(astd_task);
}
static void process_asts(void)
{
struct dlm_ls *ls = NULL;
struct dlm_rsb *r = NULL;
struct dlm_lkb *lkb;
void (*cast) (void *astparam);
void (*bast) (void *astparam, int mode);
int type = 0, found, bastmode;
for (;;) {
found = 0;
spin_lock(&ast_queue_lock);
list_for_each_entry(lkb, &ast_queue, lkb_astqueue) {
r = lkb->lkb_resource;
ls = r->res_ls;
if (dlm_locking_stopped(ls))
continue;
list_del(&lkb->lkb_astqueue);
type = lkb->lkb_ast_type;
lkb->lkb_ast_type = 0;
bastmode = lkb->lkb_bastmode;
found = 1;
break;
}
spin_unlock(&ast_queue_lock);
if (!found)
break;
cast = lkb->lkb_astfn;
bast = lkb->lkb_bastfn;
if ((type & AST_COMP) && cast)
cast(lkb->lkb_astparam);
if ((type & AST_BAST) && bast)
bast(lkb->lkb_astparam, bastmode);
/* this removes the reference added by dlm_add_ast
and may result in the lkb being freed */
dlm_put_lkb(lkb);
cond_resched();
}
}
static inline int no_asts(void)
{
int ret;
spin_lock(&ast_queue_lock);
ret = list_empty(&ast_queue);
spin_unlock(&ast_queue_lock);
return ret;
}
static int dlm_astd(void *data)
{
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
if (!test_bit(WAKE_ASTS, &astd_wakeflags))
schedule();
set_current_state(TASK_RUNNING);
mutex_lock(&astd_running);
if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags))
process_asts();
mutex_unlock(&astd_running);
}
return 0;
}
void dlm_astd_wake(void)
{
if (!no_asts()) {
set_bit(WAKE_ASTS, &astd_wakeflags);
wake_up_process(astd_task);
}
}
int dlm_astd_start(void)
{
struct task_struct *p;
int error = 0;
INIT_LIST_HEAD(&ast_queue);
spin_lock_init(&ast_queue_lock);
mutex_init(&astd_running);
p = kthread_run(dlm_astd, NULL, "dlm_astd");
if (IS_ERR(p))
error = PTR_ERR(p);
else
astd_task = p;
return error;
}
void dlm_astd_stop(void)
{
kthread_stop(astd_task);
}
void dlm_astd_suspend(void)
{
mutex_lock(&astd_running);
}
void dlm_astd_resume(void)
{
mutex_unlock(&astd_running);
}
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