1/*
2 * Copyright (c) 2007 Cisco Systems, Inc. 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/slab.h>
34
35#include "mlx4_ib.h"
36
37struct mlx4_ib_user_db_page {
38	struct list_head	list;
39	struct ib_umem	       *umem;
40	unsigned long		user_virt;
41	int			refcnt;
42};
43
44int mlx4_ib_db_map_user(struct mlx4_ib_ucontext *context, unsigned long virt,
45			struct mlx4_db *db)
46{
47	struct mlx4_ib_user_db_page *page;
48	int err = 0;
49
50	mutex_lock(&context->db_page_mutex);
51
52	list_for_each_entry(page, &context->db_page_list, list)
53		if (page->user_virt == (virt & PAGE_MASK))
54			goto found;
55
56	page = kmalloc(sizeof *page, GFP_KERNEL);
57	if (!page) {
58		err = -ENOMEM;
59		goto out;
60	}
61
62	page->user_virt = (virt & PAGE_MASK);
63	page->refcnt    = 0;
64	page->umem      = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
65				      PAGE_SIZE, 0, 0);
66	if (IS_ERR(page->umem)) {
67		err = PTR_ERR(page->umem);
68		kfree(page);
69		goto out;
70	}
71
72	list_add(&page->list, &context->db_page_list);
73
74found:
75	db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
76	db->u.user_page = page;
77	++page->refcnt;
78
79out:
80	mutex_unlock(&context->db_page_mutex);
81
82	return err;
83}
84
85void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_db *db)
86{
87	mutex_lock(&context->db_page_mutex);
88
89	if (!--db->u.user_page->refcnt) {
90		list_del(&db->u.user_page->list);
91		ib_umem_release(db->u.user_page->umem);
92		kfree(db->u.user_page);
93	}
94
95	mutex_unlock(&context->db_page_mutex);
96}
97