1/*
2 * Copyright (c) 2013-2015, Mellanox Technologies. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses.  You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 *     Redistribution and use in source and binary forms, with or
11 *     without modification, are permitted provided that the following
12 *     conditions are met:
13 *
14 *      - Redistributions of source code must retain the above
15 *        copyright notice, this list of conditions and the following
16 *        disclaimer.
17 *
18 *      - Redistributions in binary form must reproduce the above
19 *        copyright notice, this list of conditions and the following
20 *        disclaimer in the documentation and/or other materials
21 *        provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 */
32
33#include <linux/kref.h>
34#include <linux/slab.h>
35#include <rdma/ib_umem.h>
36
37#include "mlx5_ib.h"
38
39struct mlx5_ib_user_db_page {
40	struct list_head	list;
41	struct ib_umem	       *umem;
42	unsigned long		user_virt;
43	int			refcnt;
44};
45
46int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
47			struct mlx5_db *db)
48{
49	struct mlx5_ib_user_db_page *page;
50	int err = 0;
51
52	mutex_lock(&context->db_page_mutex);
53
54	list_for_each_entry(page, &context->db_page_list, list)
55		if (page->user_virt == (virt & PAGE_MASK))
56			goto found;
57
58	page = kmalloc(sizeof(*page), GFP_KERNEL);
59	if (!page) {
60		err = -ENOMEM;
61		goto out;
62	}
63
64	page->user_virt = (virt & PAGE_MASK);
65	page->refcnt    = 0;
66	page->umem      = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
67				      PAGE_SIZE, 0, 0);
68	if (IS_ERR(page->umem)) {
69		err = PTR_ERR(page->umem);
70		kfree(page);
71		goto out;
72	}
73
74	list_add(&page->list, &context->db_page_list);
75
76found:
77	db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
78	db->u.user_page = page;
79	++page->refcnt;
80
81out:
82	mutex_unlock(&context->db_page_mutex);
83
84	return err;
85}
86
87void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
88{
89	mutex_lock(&context->db_page_mutex);
90
91	if (!--db->u.user_page->refcnt) {
92		list_del(&db->u.user_page->list);
93		ib_umem_release(db->u.user_page->umem);
94		kfree(db->u.user_page);
95	}
96
97	mutex_unlock(&context->db_page_mutex);
98}
99