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  * $FreeBSD$
26  */
27 
28 #include "opt_rss.h"
29 #include "opt_ratelimit.h"
30 
31 #include <linux/kref.h>
32 #include <linux/slab.h>
33 #include <rdma/ib_umem.h>
34 
35 #include <dev/mlx5/mlx5_ib/mlx5_ib.h>
36 
37 struct mlx5_ib_user_db_page {
38 	struct list_head	list;
39 	struct ib_umem	       *umem;
40 	unsigned long		user_virt;
41 	int			refcnt;
42 };
43 
44 int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
45 			struct mlx5_db *db)
46 {
47 	struct mlx5_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 
85 void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_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