/*-
 * Copyright (c) 2013-2015, Mellanox Technologies, Ltd.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS `AS IS' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "opt_rss.h"
#include "opt_ratelimit.h"

#include <linux/kref.h>
#include <linux/slab.h>
#include <rdma/ib_umem.h>

#include <dev/mlx5/mlx5_ib/mlx5_ib.h>

struct mlx5_ib_user_db_page {
        struct list_head        list;
        struct ib_umem         *umem;
        unsigned long           user_virt;
        int                     refcnt;
};

int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
                        struct mlx5_db *db)
{
        struct mlx5_ib_user_db_page *page;
        int err = 0;

        mutex_lock(&context->db_page_mutex);

        list_for_each_entry(page, &context->db_page_list, list)
                if (page->user_virt == (virt & PAGE_MASK))
                        goto found;

        page = kmalloc(sizeof(*page), GFP_KERNEL);
        if (!page) {
                err = -ENOMEM;
                goto out;
        }

        page->user_virt = (virt & PAGE_MASK);
        page->refcnt    = 0;
        page->umem      = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
                                      PAGE_SIZE, 0, 0);
        if (IS_ERR(page->umem)) {
                err = PTR_ERR(page->umem);
                kfree(page);
                goto out;
        }

        list_add(&page->list, &context->db_page_list);

found:
        db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
        db->u.user_page = page;
        ++page->refcnt;

out:
        mutex_unlock(&context->db_page_mutex);

        return err;
}

void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
{
        mutex_lock(&context->db_page_mutex);

        if (!--db->u.user_page->refcnt) {
                list_del(&db->u.user_page->list);
                ib_umem_release(db->u.user_page->umem);
                kfree(db->u.user_page);
        }

        mutex_unlock(&context->db_page_mutex);
}