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-rw-r--r--fs/dlm/ast.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
new file mode 100644
index 0000000000..1f2f70a1b8
--- /dev/null
+++ b/fs/dlm/ast.c
@@ -0,0 +1,271 @@
+// 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);
+}
+