1 /*-
2 * Copyright (c) 2013-2015, Mellanox Technologies, Ltd. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS `AS IS' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * $FreeBSD: stable/12/sys/dev/mlx5/mlx5_ib/mlx5_ib_doorbell.c 326169 2017-11-24 14:50:28Z hselasky $
26 */
27
28 #include <linux/kref.h>
29 #include <linux/slab.h>
30 #include <rdma/ib_umem.h>
31
32 #include "mlx5_ib.h"
33
34 struct mlx5_ib_user_db_page {
35 struct list_head list;
36 struct ib_umem *umem;
37 unsigned long user_virt;
38 int refcnt;
39 };
40
mlx5_ib_db_map_user(struct mlx5_ib_ucontext * context,unsigned long virt,struct mlx5_db * db)41 int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
42 struct mlx5_db *db)
43 {
44 struct mlx5_ib_user_db_page *page;
45 int err = 0;
46
47 mutex_lock(&context->db_page_mutex);
48
49 list_for_each_entry(page, &context->db_page_list, list)
50 if (page->user_virt == (virt & PAGE_MASK))
51 goto found;
52
53 page = kmalloc(sizeof(*page), GFP_KERNEL);
54 if (!page) {
55 err = -ENOMEM;
56 goto out;
57 }
58
59 page->user_virt = (virt & PAGE_MASK);
60 page->refcnt = 0;
61 page->umem = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
62 PAGE_SIZE, 0, 0);
63 if (IS_ERR(page->umem)) {
64 err = PTR_ERR(page->umem);
65 kfree(page);
66 goto out;
67 }
68
69 list_add(&page->list, &context->db_page_list);
70
71 found:
72 db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
73 db->u.user_page = page;
74 ++page->refcnt;
75
76 out:
77 mutex_unlock(&context->db_page_mutex);
78
79 return err;
80 }
81
mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext * context,struct mlx5_db * db)82 void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
83 {
84 mutex_lock(&context->db_page_mutex);
85
86 if (!--db->u.user_page->refcnt) {
87 list_del(&db->u.user_page->list);
88 ib_umem_release(db->u.user_page->umem);
89 kfree(db->u.user_page);
90 }
91
92 mutex_unlock(&context->db_page_mutex);
93 }
94