// SPDX-License-Identifier: GPL-2.0#include <linux/slab.h>#include <linux/spinlock.h>#include <linux/once.h>#include <linux/random.h> struct once_work {	struct work_struct work;	struct static_key_true *key;}; static void once_deferred(struct work_struct *w){	struct once_work *work; 	work = container_of(w, struct once_work, work);	BUG_ON(!static_key_enabled(work->key));	static_branch_disable(work->key);	kfree(work);} static void once_disable_jump(struct static_key_true *key){	struct once_work *w; 	w = kmalloc(sizeof(*w), GFP_ATOMIC);	if (!w)		return; 	INIT_WORK(&w->work, once_deferred);	w->key = key;	schedule_work(&w->work);} static DEFINE_SPINLOCK(once_lock); bool __do_once_start(bool *done, unsigned long *flags)	__acquires(once_lock){	spin_lock_irqsave(&once_lock, *flags);	if (*done) {		spin_unlock_irqrestore(&once_lock, *flags);		/* Keep sparse happy by restoring an even lock count on		 * this lock. In case we return here, we don't call into		 * __do_once_done but return early in the DO_ONCE() macro.		 */		__acquire(once_lock);		return false;	} 	return true;}EXPORT_SYMBOL(__do_once_start); void __do_once_done(bool *done, struct static_key_true *once_key,		    unsigned long *flags)	__releases(once_lock){	*done = true;	spin_unlock_irqrestore(&once_lock, *flags);	once_disable_jump(once_key);}EXPORT_SYMBOL(__do_once_done);