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 
26 #include "opt_rss.h"
27 #include "opt_ratelimit.h"
28 
29 #include <linux/kref.h>
30 #include <linux/slab.h>
31 #include <rdma/ib_umem.h>
32 
33 #include <dev/mlx5/mlx5_ib/mlx5_ib.h>
34 
35 struct mlx5_ib_user_db_page {
36 	struct list_head	list;
37 	struct ib_umem	       *umem;
38 	unsigned long		user_virt;
39 	int			refcnt;
40 };
41 
42 int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
43 			struct mlx5_db *db)
44 {
45 	struct mlx5_ib_user_db_page *page;
46 	int err = 0;
47 
48 	mutex_lock(&context->db_page_mutex);
49 
50 	list_for_each_entry(page, &context->db_page_list, list)
51 		if (page->user_virt == (virt & PAGE_MASK))
52 			goto found;
53 
54 	page = kmalloc(sizeof(*page), GFP_KERNEL);
55 	if (!page) {
56 		err = -ENOMEM;
57 		goto out;
58 	}
59 
60 	page->user_virt = (virt & PAGE_MASK);
61 	page->refcnt    = 0;
62 	page->umem      = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
63 				      PAGE_SIZE, 0, 0);
64 	if (IS_ERR(page->umem)) {
65 		err = PTR_ERR(page->umem);
66 		kfree(page);
67 		goto out;
68 	}
69 
70 	list_add(&page->list, &context->db_page_list);
71 
72 found:
73 	db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
74 	db->u.user_page = page;
75 	++page->refcnt;
76 
77 out:
78 	mutex_unlock(&context->db_page_mutex);
79 
80 	return err;
81 }
82 
83 void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
84 {
85 	mutex_lock(&context->db_page_mutex);
86 
87 	if (!--db->u.user_page->refcnt) {
88 		list_del(&db->u.user_page->list);
89 		ib_umem_release(db->u.user_page->umem);
90 		kfree(db->u.user_page);
91 	}
92 
93 	mutex_unlock(&context->db_page_mutex);
94 }
95