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#include <rdma/uverbs_ioctl.h>
35
36#include "mlx4_ib.h"
37
38struct mlx4_ib_user_db_page {
39	struct list_head	list;
40	struct ib_umem	       *umem;
41	unsigned long		user_virt;
42	int			refcnt;
43};
44
45int mlx4_ib_db_map_user(struct ib_udata *udata, unsigned long virt,
46			struct mlx4_db *db)
47{
48	struct mlx4_ib_user_db_page *page;
49	int err = 0;
50	struct mlx4_ib_ucontext *context = rdma_udata_to_drv_context(
51		udata, struct mlx4_ib_ucontext, ibucontext);
52
53	mutex_lock(&context->db_page_mutex);
54
55	list_for_each_entry(page, &context->db_page_list, list)
56		if (page->user_virt == (virt & PAGE_MASK))
57			goto found;
58
59	page = kmalloc(sizeof *page, GFP_KERNEL);
60	if (!page) {
61		err = -ENOMEM;
62		goto out;
63	}
64
65	page->user_virt = (virt & PAGE_MASK);
66	page->refcnt    = 0;
67	page->umem = ib_umem_get(context->ibucontext.device, virt & PAGE_MASK,
68				 PAGE_SIZE, 0);
69	if (IS_ERR(page->umem)) {
70		err = PTR_ERR(page->umem);
71		kfree(page);
72		goto out;
73	}
74
75	list_add(&page->list, &context->db_page_list);
76
77found:
78	db->dma = sg_dma_address(page->umem->sgt_append.sgt.sgl) +
79		  (virt & ~PAGE_MASK);
80	db->u.user_page = page;
81	++page->refcnt;
82
83out:
84	mutex_unlock(&context->db_page_mutex);
85
86	return err;
87}
88
89void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_db *db)
90{
91	mutex_lock(&context->db_page_mutex);
92
93	if (!--db->u.user_page->refcnt) {
94		list_del(&db->u.user_page->list);
95		ib_umem_release(db->u.user_page->umem);
96		kfree(db->u.user_page);
97	}
98
99	mutex_unlock(&context->db_page_mutex);
100}
101