/*-
 * 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.
 *
 * $FreeBSD$
 */

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

#include "mlx5_ib.h"

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

int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, uintptr_t virt,
			struct mlx5_db *db)
{
	struct mlx5_ib_user_db_page *page;
	struct ib_umem_chunk *chunk;
	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:
	chunk = list_entry(page->umem->chunk_list.next,
	    struct ib_umem_chunk, list);
	db->dma = sg_dma_address(chunk->page_list) + (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);
}