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 <linux/sched/mm.h>
36 #include <rdma/ib_umem.h>
37
38 #include "mlx5_ib.h"
39
40 struct mlx5_ib_user_db_page {
41 struct list_head list;
42 struct ib_umem *umem;
43 unsigned long user_virt;
44 int refcnt;
45 struct mm_struct *mm;
46 };
47
mlx5_ib_db_map_user(struct mlx5_ib_ucontext * context,unsigned long virt,struct mlx5_db * db)48 int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
49 struct mlx5_db *db)
50 {
51 struct mlx5_ib_user_db_page *page;
52 int err = 0;
53
54 mutex_lock(&context->db_page_mutex);
55
56 list_for_each_entry(page, &context->db_page_list, list)
57 if ((current->mm == page->mm) &&
58 (page->user_virt == (virt & PAGE_MASK)))
59 goto found;
60
61 page = kmalloc(sizeof(*page), GFP_KERNEL);
62 if (!page) {
63 err = -ENOMEM;
64 goto out;
65 }
66
67 page->user_virt = (virt & PAGE_MASK);
68 page->refcnt = 0;
69 page->umem = ib_umem_get(context->ibucontext.device, virt & PAGE_MASK,
70 PAGE_SIZE, 0);
71 if (IS_ERR(page->umem)) {
72 err = PTR_ERR(page->umem);
73 kfree(page);
74 goto out;
75 }
76 mmgrab(current->mm);
77 page->mm = current->mm;
78
79 list_add(&page->list, &context->db_page_list);
80
81 found:
82 db->dma = sg_dma_address(page->umem->sgt_append.sgt.sgl) +
83 (virt & ~PAGE_MASK);
84 db->u.user_page = page;
85 ++page->refcnt;
86
87 out:
88 mutex_unlock(&context->db_page_mutex);
89
90 return err;
91 }
92
mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext * context,struct mlx5_db * db)93 void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
94 {
95 mutex_lock(&context->db_page_mutex);
96
97 if (!--db->u.user_page->refcnt) {
98 list_del(&db->u.user_page->list);
99 mmdrop(db->u.user_page->mm);
100 ib_umem_release(db->u.user_page->umem);
101 kfree(db->u.user_page);
102 }
103
104 mutex_unlock(&context->db_page_mutex);
105 }
106