mlx5_ib_doorbell.c revision 331769 
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/11/sys/dev/mlx5/mlx5_ib/mlx5_ib_doorbell.c 331769 2018-03-30 18:06:29Z 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
34struct 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
41int 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
71found:
72	db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
73	db->u.user_page = page;
74	++page->refcnt;
75
76out:
77	mutex_unlock(&context->db_page_mutex);
78
79	return err;
80}
81
82void 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