/*
 * Copyright (c) 2007 Cisco Systems, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - 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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/slab.h>
#include <rdma/uverbs_ioctl.h>

#include "mlx4_ib.h"

struct mlx4_ib_user_db_page {
        struct list_head        list;
        struct ib_umem         *umem;
        unsigned long           user_virt;
        int                     refcnt;
};

int mlx4_ib_db_map_user(struct ib_udata *udata, unsigned long virt,
                        struct mlx4_db *db)
{
        struct mlx4_ib_user_db_page *page;
        int err = 0;
        struct mlx4_ib_ucontext *context = rdma_udata_to_drv_context(
                udata, struct mlx4_ib_ucontext, ibucontext);

        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_obj(*page);
        if (!page) {
                err = -ENOMEM;
                goto out;
        }

        page->user_virt = (virt & PAGE_MASK);
        page->refcnt    = 0;
        page->umem = ib_umem_get(context->ibucontext.device, virt & PAGE_MASK,
                                 PAGE_SIZE, 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->sgt_append.sgt.sgl) +
                  (virt & ~PAGE_MASK);
        db->u.user_page = page;
        ++page->refcnt;

out:
        mutex_unlock(&context->db_page_mutex);

        return err;
}

void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_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);
}