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// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2010 Red Hat, Inc. All rights reserved.
**
**
*******************************************************************************
******************************************************************************/
#include <trace/events/dlm.h>
#include "dlm_internal.h"
#include "memory.h"
#include "lock.h"
#include "user.h"
#include "ast.h"
void dlm_release_callback(struct kref *ref)
{
struct dlm_callback *cb = container_of(ref, struct dlm_callback, ref);
dlm_free_cb(cb);
}
void dlm_callback_set_last_ptr(struct dlm_callback **from,
struct dlm_callback *to)
{
if (*from)
kref_put(&(*from)->ref, dlm_release_callback);
if (to)
kref_get(&to->ref);
*from = to;
}
int dlm_enqueue_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
int status, uint32_t sbflags)
{
struct dlm_ls *ls = lkb->lkb_resource->res_ls;
int rv = DLM_ENQUEUE_CALLBACK_SUCCESS;
struct dlm_callback *cb;
int prev_mode;
if (flags & DLM_CB_BAST) {
/* if cb is a bast, it should be skipped if the blocking mode is
* compatible with the last granted mode
*/
if (lkb->lkb_last_cast) {
if (dlm_modes_compat(mode, lkb->lkb_last_cast->mode)) {
log_debug(ls, "skip %x bast mode %d for cast mode %d",
lkb->lkb_id, mode,
lkb->lkb_last_cast->mode);
goto out;
}
}
/*
* Suppress some redundant basts here, do more on removal.
* Don't even add a bast if the callback just before it
* is a bast for the same mode or a more restrictive mode.
* (the addional > PR check is needed for PR/CW inversion)
*/
if (lkb->lkb_last_cb && lkb->lkb_last_cb->flags & DLM_CB_BAST) {
prev_mode = lkb->lkb_last_cb->mode;
if ((prev_mode == mode) ||
(prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
log_debug(ls, "skip %x add bast mode %d for bast mode %d",
lkb->lkb_id, mode, prev_mode);
goto out;
}
}
}
cb = dlm_allocate_cb();
if (!cb) {
rv = DLM_ENQUEUE_CALLBACK_FAILURE;
goto out;
}
cb->flags = flags;
cb->mode = mode;
cb->sb_status = status;
cb->sb_flags = (sbflags & 0x000000FF);
kref_init(&cb->ref);
if (!test_and_set_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags))
rv = DLM_ENQUEUE_CALLBACK_NEED_SCHED;
list_add_tail(&cb->list, &lkb->lkb_callbacks);
if (flags & DLM_CB_CAST)
dlm_callback_set_last_ptr(&lkb->lkb_last_cast, cb);
dlm_callback_set_last_ptr(&lkb->lkb_last_cb, cb);
out:
return rv;
}
int dlm_dequeue_lkb_callback(struct dlm_lkb *lkb, struct dlm_callback **cb)
{
/* oldest undelivered cb is callbacks first entry */
*cb = list_first_entry_or_null(&lkb->lkb_callbacks,
struct dlm_callback, list);
if (!*cb)
return DLM_DEQUEUE_CALLBACK_EMPTY;
/* remove it from callbacks so shift others down */
list_del(&(*cb)->list);
if (list_empty(&lkb->lkb_callbacks))
return DLM_DEQUEUE_CALLBACK_LAST;
return DLM_DEQUEUE_CALLBACK_SUCCESS;
}
void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
uint32_t sbflags)
{
struct dlm_ls *ls = lkb->lkb_resource->res_ls;
int rv;
if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
dlm_user_add_ast(lkb, flags, mode, status, sbflags);
return;
}
spin_lock(&lkb->lkb_cb_lock);
rv = dlm_enqueue_lkb_callback(lkb, flags, mode, status, sbflags);
switch (rv) {
case DLM_ENQUEUE_CALLBACK_NEED_SCHED:
kref_get(&lkb->lkb_ref);
spin_lock(&ls->ls_cb_lock);
if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
} else {
queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
}
spin_unlock(&ls->ls_cb_lock);
break;
case DLM_ENQUEUE_CALLBACK_FAILURE:
WARN_ON_ONCE(1);
break;
case DLM_ENQUEUE_CALLBACK_SUCCESS:
break;
default:
WARN_ON_ONCE(1);
break;
}
spin_unlock(&lkb->lkb_cb_lock);
}
void dlm_callback_work(struct work_struct *work)
{
struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
struct dlm_ls *ls = lkb->lkb_resource->res_ls;
void (*castfn) (void *astparam);
void (*bastfn) (void *astparam, int mode);
struct dlm_callback *cb;
int rv;
spin_lock(&lkb->lkb_cb_lock);
rv = dlm_dequeue_lkb_callback(lkb, &cb);
if (WARN_ON_ONCE(rv == DLM_DEQUEUE_CALLBACK_EMPTY)) {
clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
spin_unlock(&lkb->lkb_cb_lock);
goto out;
}
spin_unlock(&lkb->lkb_cb_lock);
for (;;) {
castfn = lkb->lkb_astfn;
bastfn = lkb->lkb_bastfn;
if (cb->flags & DLM_CB_BAST) {
trace_dlm_bast(ls, lkb, cb->mode);
lkb->lkb_last_bast_time = ktime_get();
lkb->lkb_last_bast_mode = cb->mode;
bastfn(lkb->lkb_astparam, cb->mode);
} else if (cb->flags & DLM_CB_CAST) {
lkb->lkb_lksb->sb_status = cb->sb_status;
lkb->lkb_lksb->sb_flags = cb->sb_flags;
trace_dlm_ast(ls, lkb);
lkb->lkb_last_cast_time = ktime_get();
castfn(lkb->lkb_astparam);
}
kref_put(&cb->ref, dlm_release_callback);
spin_lock(&lkb->lkb_cb_lock);
rv = dlm_dequeue_lkb_callback(lkb, &cb);
if (rv == DLM_DEQUEUE_CALLBACK_EMPTY) {
clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
spin_unlock(&lkb->lkb_cb_lock);
break;
}
spin_unlock(&lkb->lkb_cb_lock);
}
out:
/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
dlm_put_lkb(lkb);
}
int dlm_callback_start(struct dlm_ls *ls)
{
ls->ls_callback_wq = alloc_workqueue("dlm_callback",
WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
if (!ls->ls_callback_wq) {
log_print("can't start dlm_callback workqueue");
return -ENOMEM;
}
return 0;
}
void dlm_callback_stop(struct dlm_ls *ls)
{
if (ls->ls_callback_wq)
destroy_workqueue(ls->ls_callback_wq);
}
void dlm_callback_suspend(struct dlm_ls *ls)
{
if (ls->ls_callback_wq) {
spin_lock(&ls->ls_cb_lock);
set_bit(LSFL_CB_DELAY, &ls->ls_flags);
spin_unlock(&ls->ls_cb_lock);
flush_workqueue(ls->ls_callback_wq);
}
}
#define MAX_CB_QUEUE 25
void dlm_callback_resume(struct dlm_ls *ls)
{
struct dlm_lkb *lkb, *safe;
int count = 0, sum = 0;
bool empty;
if (!ls->ls_callback_wq)
return;
more:
spin_lock(&ls->ls_cb_lock);
list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
list_del_init(&lkb->lkb_cb_list);
queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
count++;
if (count == MAX_CB_QUEUE)
break;
}
empty = list_empty(&ls->ls_cb_delay);
if (empty)
clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
spin_unlock(&ls->ls_cb_lock);
sum += count;
if (!empty) {
count = 0;
cond_resched();
goto more;
}
if (sum)
log_rinfo(ls, "%s %d", __func__, sum);
}
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