Fix: common: index_allocator_get_index_count() returns size
[lttng-tools.git] / src / common / index-allocator.c
CommitLineData
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1/*
2 * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
3 *
4 * SPDX-License-Identifier: GPL-2.0-only
5 *
6 */
7
8#include <assert.h>
9#include <inttypes.h>
10
11#include <urcu.h>
12#include <urcu/list.h>
13
14#include "macros.h"
15#include "error.h"
16
17#include "index-allocator.h"
18
19struct lttng_index_allocator {
20 struct cds_list_head unused_list;
21 uint64_t size;
22 uint64_t position;
5e09ab50 23 uint64_t nb_allocated_indexes;
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24};
25
26struct lttng_index {
27 uint64_t index;
28 struct cds_list_head head;
29};
30
31struct lttng_index_allocator *lttng_index_allocator_create(
32 uint64_t index_count)
33{
34 struct lttng_index_allocator *allocator = NULL;
35
36 allocator = zmalloc(sizeof(*allocator));
37 if (!allocator) {
38 PERROR("Failed to allocate index allocator");
39 goto end;
40 }
41
42 allocator->size = index_count;
43 allocator->position = 0;
5e09ab50 44 allocator->nb_allocated_indexes = 0;
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45
46 CDS_INIT_LIST_HEAD(&allocator->unused_list);
47
48end:
49 return allocator;
50}
51
52uint64_t lttng_index_allocator_get_index_count(struct lttng_index_allocator *allocator)
53{
5e09ab50 54 return allocator->nb_allocated_indexes;
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55}
56
57enum lttng_index_allocator_status lttng_index_allocator_alloc(
58 struct lttng_index_allocator *allocator,
59 uint64_t *allocated_index)
60{
61 enum lttng_index_allocator_status status =
62 LTTNG_INDEX_ALLOCATOR_STATUS_OK;
63
64 if (cds_list_empty(&allocator->unused_list)) {
65 if (allocator->position >= allocator->size) {
66 /* No indices left. */
67 status = LTTNG_INDEX_ALLOCATOR_STATUS_EMPTY;
68 goto end;
69 }
70
71 *allocated_index = allocator->position++;
72 } else {
73 struct lttng_index *index;
74
75 index = cds_list_first_entry(&allocator->unused_list,
76 typeof(*index), head);
77 cds_list_del(&index->head);
78 *allocated_index = index->index;
79 free(index);
80 }
81
5e09ab50 82 allocator->nb_allocated_indexes++;
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83end:
84 return status;
85}
86
87enum lttng_index_allocator_status lttng_index_allocator_release(
88 struct lttng_index_allocator *allocator, uint64_t idx)
89{
90 struct lttng_index *index = NULL;
91 enum lttng_index_allocator_status status =
92 LTTNG_INDEX_ALLOCATOR_STATUS_OK;
93
94 assert(idx < allocator->size);
95
96 index = zmalloc(sizeof(*index));
97 if (!index) {
98 PERROR("Failed to allocate free index queue");
99 status = LTTNG_INDEX_ALLOCATOR_STATUS_ERROR;
100 goto end;
101 }
102
103 index->index = idx;
104 cds_list_add_tail(&index->head, &allocator->unused_list);
5e09ab50 105 allocator->nb_allocated_indexes--;
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106
107end:
108 return status;
109}
110
111void lttng_index_allocator_destroy(struct lttng_index_allocator *allocator)
112{
113 struct lttng_index *index = NULL, *tmp_index = NULL;
114
115 if (!allocator) {
116 return;
117 }
118
119 if (lttng_index_allocator_get_index_count(allocator) > 0) {
120 WARN("Destroying index allocator with %" PRIu64
121 " slot indexes still in use",
122 lttng_index_allocator_get_index_count(allocator));
123 }
124
125 cds_list_for_each_entry_safe(index, tmp_index,
126 &allocator->unused_list, head) {
127 cds_list_del(&index->head);
128 free(index);
129 }
130
131 free(allocator);
132}
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