tasks: add put_task_struct_many()

put_task_struct_many() is as put_task_struct() but puts several
references at once. Useful to batching it.

Signed-off-by: Pavel Begunkov <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: isilence

include/linux/sched/task.h

@@ -126,6 +126,12 @@ static inline void put_task_struct(struct task_struct *t)
 		__put_task_struct(t);
 }
 
+static inline void put_task_struct_many(struct task_struct *t, int nr)
+{
+	if (refcount_sub_and_test(nr, &t->usage))
+		__put_task_struct(t);
+}
+
 void put_task_struct_rcu_user(struct task_struct *task);
 
 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT