/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (c) 2022, Microsoft Corporation.
 *
 * Authors:
 *   Beau Belgrave <beaub@linux.microsoft.com>
 */

#ifndef _LINUX_USER_EVENTS_H
#define _LINUX_USER_EVENTS_H

#include <linux/list.h>
#include <linux/refcount.h>
#include <linux/mm_types.h>
#include <linux/workqueue.h>
#include <uapi/linux/user_events.h>

#ifdef CONFIG_USER_EVENTS
struct user_event_mm {
        struct list_head        mms_link;
        struct list_head        enablers;
        struct mm_struct        *mm;
        /* Used for one-shot lists, protected by event_mutex */
        struct user_event_mm    *next;
        refcount_t              refcnt;
        refcount_t              tasks;
        struct rcu_work         put_rwork;
};

extern void user_event_mm_dup(struct task_struct *t,
                              struct user_event_mm *old_mm);

extern void user_event_mm_remove(struct task_struct *t);

static inline void user_events_fork(struct task_struct *t,
                                    u64 clone_flags)
{
        struct user_event_mm *old_mm;

        if (!t || !current->user_event_mm)
                return;

        old_mm = current->user_event_mm;

        if (clone_flags & CLONE_VM) {
                t->user_event_mm = old_mm;
                refcount_inc(&old_mm->tasks);
                return;
        }

        user_event_mm_dup(t, old_mm);
}

static inline void user_events_execve(struct task_struct *t)
{
        if (!t || !t->user_event_mm)
                return;

        user_event_mm_remove(t);
}

static inline void user_events_exit(struct task_struct *t)
{
        if (!t || !t->user_event_mm)
                return;

        user_event_mm_remove(t);
}
#else
static inline void user_events_fork(struct task_struct *t,
                                    u64 clone_flags)
{
}

static inline void user_events_execve(struct task_struct *t)
{
}

static inline void user_events_exit(struct task_struct *t)
{
}
#endif /* CONFIG_USER_EVENTS */

#endif /* _LINUX_USER_EVENTS_H */