Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
index 562fa8c..283c7b9 100644
--- a/fs/dlm/ast.c
+++ b/fs/dlm/ast.c
@@ -1,12 +1,10 @@
+// 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.
 **
-**  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.
 **
 *******************************************************************************
 ******************************************************************************/
@@ -292,6 +290,8 @@
 		flush_workqueue(ls->ls_callback_wq);
 }
 
+#define MAX_CB_QUEUE 25
+
 void dlm_callback_resume(struct dlm_ls *ls)
 {
 	struct dlm_lkb *lkb, *safe;
@@ -302,15 +302,23 @@
 	if (!ls->ls_callback_wq)
 		return;
 
+more:
 	mutex_lock(&ls->ls_cb_mutex);
 	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;
 	}
 	mutex_unlock(&ls->ls_cb_mutex);
 
 	if (count)
 		log_rinfo(ls, "dlm_callback_resume %d", count);
+	if (count == MAX_CB_QUEUE) {
+		count = 0;
+		cond_resched();
+		goto more;
+	}
 }