dbrec.c revision 331769 
1/*
2 * Copyright (c) 2005 Topspin Communications.  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#define _GNU_SOURCE
33#include <config.h>
34
35#include <stdlib.h>
36#include <pthread.h>
37#include <string.h>
38
39#include "mlx4.h"
40
41struct mlx4_db_page {
42	struct mlx4_db_page	       *prev, *next;
43	struct mlx4_buf			buf;
44	int				num_db;
45	int				use_cnt;
46	unsigned long			free[0];
47};
48
49static const int db_size[] = {
50	[MLX4_DB_TYPE_CQ] = 8,
51	[MLX4_DB_TYPE_RQ] = 4,
52};
53
54static struct mlx4_db_page *__add_page(struct mlx4_context *context,
55				       enum mlx4_db_type type)
56{
57	struct mlx4_db_page *page;
58	int ps = to_mdev(context->ibv_ctx.device)->page_size;
59	int pp;
60	int i;
61
62	pp = ps / db_size[type];
63
64	page = malloc(sizeof *page + pp / 8);
65	if (!page)
66		return NULL;
67
68	if (mlx4_alloc_buf(&page->buf, ps, ps)) {
69		free(page);
70		return NULL;
71	}
72
73	page->num_db  = pp;
74	page->use_cnt = 0;
75	for (i = 0; i < pp / (sizeof (long) * 8); ++i)
76		page->free[i] = ~0;
77
78	page->prev = NULL;
79	page->next = context->db_list[type];
80	context->db_list[type] = page;
81	if (page->next)
82		page->next->prev = page;
83
84	return page;
85}
86
87uint32_t *mlx4_alloc_db(struct mlx4_context *context, enum mlx4_db_type type)
88{
89	struct mlx4_db_page *page;
90	uint32_t *db = NULL;
91	int i, j;
92
93	pthread_mutex_lock(&context->db_list_mutex);
94
95	for (page = context->db_list[type]; page; page = page->next)
96		if (page->use_cnt < page->num_db)
97			goto found;
98
99	page = __add_page(context, type);
100	if (!page)
101		goto out;
102
103found:
104	++page->use_cnt;
105
106	for (i = 0; !page->free[i]; ++i)
107		/* nothing */;
108
109	j = ffsl(page->free[i]);
110	page->free[i] &= ~(1UL << (j - 1));
111	db = page->buf.buf + (i * 8 * sizeof (long) + (j - 1)) * db_size[type];
112
113out:
114	pthread_mutex_unlock(&context->db_list_mutex);
115
116	return db;
117}
118
119void mlx4_free_db(struct mlx4_context *context, enum mlx4_db_type type, uint32_t *db)
120{
121	struct mlx4_db_page *page;
122	uintptr_t ps = to_mdev(context->ibv_ctx.device)->page_size;
123	int i;
124
125	pthread_mutex_lock(&context->db_list_mutex);
126
127	for (page = context->db_list[type]; page; page = page->next)
128		if (((uintptr_t) db & ~(ps - 1)) == (uintptr_t) page->buf.buf)
129			break;
130
131	if (!page)
132		goto out;
133
134	i = ((void *) db - page->buf.buf) / db_size[type];
135	page->free[i / (8 * sizeof (long))] |= 1UL << (i % (8 * sizeof (long)));
136
137	if (!--page->use_cnt) {
138		if (page->prev)
139			page->prev->next = page->next;
140		else
141			context->db_list[type] = page->next;
142		if (page->next)
143			page->next->prev = page->prev;
144
145		mlx4_free_buf(&page->buf);
146		free(page);
147	}
148
149out:
150	pthread_mutex_unlock(&context->db_list_mutex);
151}
152