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
39 struct 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
46 int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context,
47 struct ib_udata *udata, unsigned long virt,
48 struct mlx5_db *db)
49 {
50 struct mlx5_ib_user_db_page *page;
51 int err = 0;
52
53 mutex_lock(&context->db_page_mutex);
54
55 list_for_each_entry(page, &context->db_page_list, list)
56 if (page->user_virt == (virt & PAGE_MASK))
57 goto found;
58
59 page = kmalloc(sizeof(*page), GFP_KERNEL);
60 if (!page) {
61 err = -ENOMEM;
62 goto out;
63 }
64
65 page->user_virt = (virt & PAGE_MASK);
66 page->refcnt = 0;
67 page->umem = ib_umem_get(udata, virt & PAGE_MASK, 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
76 found:
77 db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
78 db->u.user_page = page;
79 ++page->refcnt;
80
81 out:
82 mutex_unlock(&context->db_page_mutex);
83
84 return err;
85 }
86
87 void 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 }