fs/proc: do_task_stat: use __for_each_thread()

do/while_each_thread should be avoided when possible.

Link: https://lkml.kernel.org/r/20230909164501.GA11581@redhat.comSigned-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/proc/array.c

@@ -536,12 +536,13 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 
 		/* add up live thread stats at the group level */
 		if (whole) {
-			struct task_struct *t = task;
-			do {
+			struct task_struct *t;
+
+			__for_each_thread(sig, t) {
 				min_flt += t->min_flt;
 				maj_flt += t->maj_flt;
 				gtime += task_gtime(t);
-			} while_each_thread(task, t);
+			}
 
 			min_flt += sig->min_flt;
 			maj_flt += sig->maj_flt;