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![Alexander Aring](/assets/img/avatar_default.png)
This patch moves the dlm_purge_lkb_callbacks() function from ast to user dlm module as it is only a function being used by dlm user implementation. I got be hinted to hold specific locks regarding the callback handling for dlm_purge_lkb_callbacks() but it was false positive. It is confusing because ast dlm implementation uses a different locking behaviour as user locks uses as DLM handles kernel and user dlm locks differently. To avoid the confusing we move this function to dlm user implementation. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
271 lines
6.6 KiB
C
271 lines
6.6 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) 2004-2010 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 <trace/events/dlm.h>
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#include "dlm_internal.h"
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#include "memory.h"
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#include "lock.h"
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#include "user.h"
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#include "ast.h"
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void dlm_release_callback(struct kref *ref)
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{
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struct dlm_callback *cb = container_of(ref, struct dlm_callback, ref);
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dlm_free_cb(cb);
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}
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void dlm_callback_set_last_ptr(struct dlm_callback **from,
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struct dlm_callback *to)
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{
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if (*from)
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kref_put(&(*from)->ref, dlm_release_callback);
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if (to)
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kref_get(&to->ref);
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*from = to;
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}
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int dlm_enqueue_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
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int status, uint32_t sbflags)
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{
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struct dlm_ls *ls = lkb->lkb_resource->res_ls;
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int rv = DLM_ENQUEUE_CALLBACK_SUCCESS;
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struct dlm_callback *cb;
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int prev_mode;
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if (flags & DLM_CB_BAST) {
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/* if cb is a bast, it should be skipped if the blocking mode is
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* compatible with the last granted mode
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*/
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if (lkb->lkb_last_cast) {
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if (dlm_modes_compat(mode, lkb->lkb_last_cast->mode)) {
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log_debug(ls, "skip %x bast mode %d for cast mode %d",
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lkb->lkb_id, mode,
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lkb->lkb_last_cast->mode);
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goto out;
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}
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}
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/*
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* Suppress some redundant basts here, do more on removal.
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* Don't even add a bast if the callback just before it
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* is a bast for the same mode or a more restrictive mode.
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* (the addional > PR check is needed for PR/CW inversion)
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*/
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if (lkb->lkb_last_cb && lkb->lkb_last_cb->flags & DLM_CB_BAST) {
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prev_mode = lkb->lkb_last_cb->mode;
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if ((prev_mode == mode) ||
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(prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
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log_debug(ls, "skip %x add bast mode %d for bast mode %d",
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lkb->lkb_id, mode, prev_mode);
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goto out;
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}
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}
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}
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cb = dlm_allocate_cb();
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if (!cb) {
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rv = DLM_ENQUEUE_CALLBACK_FAILURE;
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goto out;
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}
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cb->flags = flags;
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cb->mode = mode;
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cb->sb_status = status;
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cb->sb_flags = (sbflags & 0x000000FF);
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kref_init(&cb->ref);
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if (!test_and_set_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags))
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rv = DLM_ENQUEUE_CALLBACK_NEED_SCHED;
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list_add_tail(&cb->list, &lkb->lkb_callbacks);
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if (flags & DLM_CB_CAST)
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dlm_callback_set_last_ptr(&lkb->lkb_last_cast, cb);
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dlm_callback_set_last_ptr(&lkb->lkb_last_cb, cb);
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out:
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return rv;
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}
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int dlm_dequeue_lkb_callback(struct dlm_lkb *lkb, struct dlm_callback **cb)
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{
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/* oldest undelivered cb is callbacks first entry */
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*cb = list_first_entry_or_null(&lkb->lkb_callbacks,
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struct dlm_callback, list);
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if (!*cb)
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return DLM_DEQUEUE_CALLBACK_EMPTY;
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/* remove it from callbacks so shift others down */
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list_del(&(*cb)->list);
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if (list_empty(&lkb->lkb_callbacks))
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return DLM_DEQUEUE_CALLBACK_LAST;
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return DLM_DEQUEUE_CALLBACK_SUCCESS;
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}
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void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
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uint32_t sbflags)
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{
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struct dlm_ls *ls = lkb->lkb_resource->res_ls;
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int rv;
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if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
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dlm_user_add_ast(lkb, flags, mode, status, sbflags);
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return;
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}
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spin_lock(&lkb->lkb_cb_lock);
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rv = dlm_enqueue_lkb_callback(lkb, flags, mode, status, sbflags);
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switch (rv) {
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case DLM_ENQUEUE_CALLBACK_NEED_SCHED:
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kref_get(&lkb->lkb_ref);
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spin_lock(&ls->ls_cb_lock);
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if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
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list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
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} else {
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queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
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}
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spin_unlock(&ls->ls_cb_lock);
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break;
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case DLM_ENQUEUE_CALLBACK_FAILURE:
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WARN_ON_ONCE(1);
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break;
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case DLM_ENQUEUE_CALLBACK_SUCCESS:
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break;
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default:
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WARN_ON_ONCE(1);
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break;
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}
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spin_unlock(&lkb->lkb_cb_lock);
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}
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void dlm_callback_work(struct work_struct *work)
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{
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struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
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struct dlm_ls *ls = lkb->lkb_resource->res_ls;
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void (*castfn) (void *astparam);
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void (*bastfn) (void *astparam, int mode);
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struct dlm_callback *cb;
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int rv;
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spin_lock(&lkb->lkb_cb_lock);
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rv = dlm_dequeue_lkb_callback(lkb, &cb);
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if (WARN_ON_ONCE(rv == DLM_DEQUEUE_CALLBACK_EMPTY)) {
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clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
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spin_unlock(&lkb->lkb_cb_lock);
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goto out;
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}
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spin_unlock(&lkb->lkb_cb_lock);
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for (;;) {
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castfn = lkb->lkb_astfn;
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bastfn = lkb->lkb_bastfn;
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if (cb->flags & DLM_CB_BAST) {
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trace_dlm_bast(ls, lkb, cb->mode);
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lkb->lkb_last_bast_time = ktime_get();
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lkb->lkb_last_bast_mode = cb->mode;
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bastfn(lkb->lkb_astparam, cb->mode);
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} else if (cb->flags & DLM_CB_CAST) {
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lkb->lkb_lksb->sb_status = cb->sb_status;
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lkb->lkb_lksb->sb_flags = cb->sb_flags;
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trace_dlm_ast(ls, lkb);
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lkb->lkb_last_cast_time = ktime_get();
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castfn(lkb->lkb_astparam);
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}
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kref_put(&cb->ref, dlm_release_callback);
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spin_lock(&lkb->lkb_cb_lock);
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rv = dlm_dequeue_lkb_callback(lkb, &cb);
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if (rv == DLM_DEQUEUE_CALLBACK_EMPTY) {
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clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
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spin_unlock(&lkb->lkb_cb_lock);
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break;
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}
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spin_unlock(&lkb->lkb_cb_lock);
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}
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out:
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/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
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dlm_put_lkb(lkb);
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}
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int dlm_callback_start(struct dlm_ls *ls)
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{
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ls->ls_callback_wq = alloc_workqueue("dlm_callback",
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WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
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if (!ls->ls_callback_wq) {
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log_print("can't start dlm_callback workqueue");
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return -ENOMEM;
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}
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return 0;
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}
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void dlm_callback_stop(struct dlm_ls *ls)
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{
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if (ls->ls_callback_wq)
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destroy_workqueue(ls->ls_callback_wq);
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}
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void dlm_callback_suspend(struct dlm_ls *ls)
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{
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if (ls->ls_callback_wq) {
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spin_lock(&ls->ls_cb_lock);
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set_bit(LSFL_CB_DELAY, &ls->ls_flags);
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spin_unlock(&ls->ls_cb_lock);
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flush_workqueue(ls->ls_callback_wq);
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}
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}
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#define MAX_CB_QUEUE 25
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void dlm_callback_resume(struct dlm_ls *ls)
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{
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struct dlm_lkb *lkb, *safe;
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int count = 0, sum = 0;
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bool empty;
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if (!ls->ls_callback_wq)
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return;
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more:
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spin_lock(&ls->ls_cb_lock);
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list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
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list_del_init(&lkb->lkb_cb_list);
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queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
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count++;
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if (count == MAX_CB_QUEUE)
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break;
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}
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empty = list_empty(&ls->ls_cb_delay);
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if (empty)
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clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
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spin_unlock(&ls->ls_cb_lock);
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sum += count;
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if (!empty) {
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count = 0;
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cond_resched();
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goto more;
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}
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if (sum)
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log_rinfo(ls, "%s %d", __func__, sum);
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}
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