/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
/*
 * Copyright(c) 2020 Cornelis Networks, Inc.
 * Copyright(c) 2016 Intel Corporation.
 */

#ifndef _HFI1_MMU_RB_H
#define _HFI1_MMU_RB_H

#include "hfi.h"

struct mmu_rb_node {
        unsigned long addr;
        unsigned long len;
        unsigned long __last;
        struct rb_node node;
        struct mmu_rb_handler *handler;
        struct list_head list;
        struct kref refcount;
};

/* filter and evict must not sleep. Only remove is allowed to sleep. */
struct mmu_rb_ops {
        bool (*filter)(struct mmu_rb_node *node, unsigned long addr,
                       unsigned long len);
        void (*remove)(void *ops_arg, struct mmu_rb_node *mnode);
        int (*evict)(void *ops_arg, struct mmu_rb_node *mnode,
                     void *evict_arg, bool *stop);
};

struct mmu_rb_handler {
        /*
         * struct mmu_notifier is 56 bytes, and spinlock_t is 4 bytes, so
         * they fit together in one cache line.  mn is relatively rarely
         * accessed, so co-locating the spinlock with it achieves much of
         * the cacheline contention reduction of giving the spinlock its own
         * cacheline without the overhead of doing so.
         */
        struct mmu_notifier mn;
        spinlock_t lock;        /* protect the RB tree */

        /* Begin on a new cachline boundary here */
        struct rb_root_cached root ____cacheline_aligned_in_smp;
        void *ops_arg;
        const struct mmu_rb_ops *ops;
        struct list_head lru_list;
        struct work_struct del_work;
        struct list_head del_list;
        struct workqueue_struct *wq;
        void *free_ptr;
};

int hfi1_mmu_rb_register(void *ops_arg,
                         const struct mmu_rb_ops *ops,
                         struct workqueue_struct *wq,
                         struct mmu_rb_handler **handler);
void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler);
int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
                       struct mmu_rb_node *mnode);
void hfi1_mmu_rb_release(struct kref *refcount);

void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg);
struct mmu_rb_node *hfi1_mmu_rb_get_first(struct mmu_rb_handler *handler,
                                          unsigned long addr,
                                          unsigned long len);

#endif /* _HFI1_MMU_RB_H */