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
37 struct 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
mlx4_ib_db_map_user(struct mlx4_ib_ucontext * context,unsigned long virt,struct mlx4_db * db)44 int 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
74 found:
75 db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
76 db->u.user_page = page;
77 ++page->refcnt;
78
79 out:
80 mutex_unlock(&context->db_page_mutex);
81
82 return err;
83 }
84
mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext * context,struct mlx4_db * db)85 void 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