trace_workqueue: use list_for_each_entry() instead of list_for_each_entry_safe()

No need to use list_for_each_entry_safe() in iteration without deleting
any node, we can use list_for_each_entry() instead.

[ Impact: cleanup ]
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

kernel/trace/trace_workqueue.c

@@ -47,12 +47,11 @@ probe_workqueue_insertion(struct task_struct *wq_thread,
 			  struct work_struct *work)
 {
 	int cpu = cpumask_first(&wq_thread->cpus_allowed);
-	struct cpu_workqueue_stats *node, *next;
+	struct cpu_workqueue_stats *node;
 	unsigned long flags;
 
 	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
-	list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
-							list) {
+	list_for_each_entry(node, &workqueue_cpu_stat(cpu)->list, list) {
 		if (node->pid == wq_thread->pid) {
 			atomic_inc(&node->inserted);
 			goto found;
@@ -69,12 +68,11 @@ probe_workqueue_execution(struct task_struct *wq_thread,
 			  struct work_struct *work)
 {
 	int cpu = cpumask_first(&wq_thread->cpus_allowed);
-	struct cpu_workqueue_stats *node, *next;
+	struct cpu_workqueue_stats *node;
 	unsigned long flags;
 
 	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
-	list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
-							list) {
+	list_for_each_entry(node, &workqueue_cpu_stat(cpu)->list, list) {
 		if (node->pid == wq_thread->pid) {
 			node->executed++;
 			goto found;