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(device: context->ibucontext.device, addr: virt & PAGE_MASK,
68 PAGE_SIZE, access: 0);
69 if (IS_ERR(ptr: page->umem)) {
70 err = PTR_ERR(ptr: page->umem);
71 kfree(objp: page);
72 goto out;
73 }
74
75 list_add(new: &page->list, head: &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(lock: &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(entry: &db->u.user_page->list);
95 ib_umem_release(umem: db->u.user_page->umem);
96 kfree(objp: db->u.user_page);
97 }
98
99 mutex_unlock(lock: &context->db_page_mutex);
100}
101

source code of linux/drivers/infiniband/hw/mlx4/doorbell.c