1/*-
2 *   BSD LICENSE
3 *
4 *   Copyright(c) 2016 Intel Corporation. All rights reserved.
5 *   All rights reserved.
6 *
7 *   Redistribution and use in source and binary forms, with or without
8 *   modification, are permitted provided that the following conditions
9 *   are met:
10 *
11 *     * Redistributions of source code must retain the above copyright
12 *       notice, this list of conditions and the following disclaimer.
13 *     * Redistributions in binary form must reproduce the above copyright
14 *       notice, this list of conditions and the following disclaimer in
15 *       the documentation and/or other materials provided with the
16 *       distribution.
17 *     * Neither the name of Intel Corporation nor the names of its
18 *       contributors may be used to endorse or promote products derived
19 *       from this software without specific prior written permission.
20 *
21 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <stdio.h>
35#include <rte_mempool.h>
36#include <rte_malloc.h>
37
38struct rte_mempool_stack {
39	rte_spinlock_t sl;
40
41	uint32_t size;
42	uint32_t len;
43	void *objs[];
44};
45
46static int
47stack_alloc(struct rte_mempool *mp)
48{
49	struct rte_mempool_stack *s;
50	unsigned n = mp->size;
51	int size = sizeof(*s) + (n+16)*sizeof(void *);
52
53	/* Allocate our local memory structure */
54	s = rte_zmalloc_socket("mempool-stack",
55			size,
56			RTE_CACHE_LINE_SIZE,
57			mp->socket_id);
58	if (s == NULL) {
59		RTE_LOG(ERR, MEMPOOL, "Cannot allocate stack!\n");
60		return -ENOMEM;
61	}
62
63	rte_spinlock_init(&s->sl);
64
65	s->size = n;
66	mp->pool_data = s;
67
68	return 0;
69}
70
71static int
72stack_enqueue(struct rte_mempool *mp, void * const *obj_table,
73		unsigned n)
74{
75	struct rte_mempool_stack *s = mp->pool_data;
76	void **cache_objs;
77	unsigned index;
78
79	rte_spinlock_lock(&s->sl);
80	cache_objs = &s->objs[s->len];
81
82	/* Is there sufficient space in the stack ? */
83	if ((s->len + n) > s->size) {
84		rte_spinlock_unlock(&s->sl);
85		return -ENOBUFS;
86	}
87
88	/* Add elements back into the cache */
89	for (index = 0; index < n; ++index, obj_table++)
90		cache_objs[index] = *obj_table;
91
92	s->len += n;
93
94	rte_spinlock_unlock(&s->sl);
95	return 0;
96}
97
98static int
99stack_dequeue(struct rte_mempool *mp, void **obj_table,
100		unsigned n)
101{
102	struct rte_mempool_stack *s = mp->pool_data;
103	void **cache_objs;
104	unsigned index, len;
105
106	rte_spinlock_lock(&s->sl);
107
108	if (unlikely(n > s->len)) {
109		rte_spinlock_unlock(&s->sl);
110		return -ENOENT;
111	}
112
113	cache_objs = s->objs;
114
115	for (index = 0, len = s->len - 1; index < n;
116			++index, len--, obj_table++)
117		*obj_table = cache_objs[len];
118
119	s->len -= n;
120	rte_spinlock_unlock(&s->sl);
121	return 0;
122}
123
124static unsigned
125stack_get_count(const struct rte_mempool *mp)
126{
127	struct rte_mempool_stack *s = mp->pool_data;
128
129	return s->len;
130}
131
132static void
133stack_free(struct rte_mempool *mp)
134{
135	rte_free((void *)(mp->pool_data));
136}
137
138static struct rte_mempool_ops ops_stack = {
139	.name = "stack",
140	.alloc = stack_alloc,
141	.free = stack_free,
142	.enqueue = stack_enqueue,
143	.dequeue = stack_dequeue,
144	.get_count = stack_get_count
145};
146
147MEMPOOL_REGISTER_OPS(ops_stack);
148