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246611b0 FD |
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 | ||
19 | struct lttng_index_allocator { | |
20 | struct cds_list_head unused_list; | |
21 | uint64_t size; | |
22 | uint64_t position; | |
23 | }; | |
24 | ||
25 | struct lttng_index { | |
26 | uint64_t index; | |
27 | struct cds_list_head head; | |
28 | }; | |
29 | ||
30 | struct lttng_index_allocator *lttng_index_allocator_create( | |
31 | uint64_t index_count) | |
32 | { | |
33 | struct lttng_index_allocator *allocator = NULL; | |
34 | ||
35 | allocator = zmalloc(sizeof(*allocator)); | |
36 | if (!allocator) { | |
37 | PERROR("Failed to allocate index allocator"); | |
38 | goto end; | |
39 | } | |
40 | ||
41 | allocator->size = index_count; | |
42 | allocator->position = 0; | |
43 | ||
44 | CDS_INIT_LIST_HEAD(&allocator->unused_list); | |
45 | ||
46 | end: | |
47 | return allocator; | |
48 | } | |
49 | ||
50 | uint64_t lttng_index_allocator_get_index_count(struct lttng_index_allocator *allocator) | |
51 | { | |
52 | return allocator->size; | |
53 | } | |
54 | ||
55 | enum lttng_index_allocator_status lttng_index_allocator_alloc( | |
56 | struct lttng_index_allocator *allocator, | |
57 | uint64_t *allocated_index) | |
58 | { | |
59 | enum lttng_index_allocator_status status = | |
60 | LTTNG_INDEX_ALLOCATOR_STATUS_OK; | |
61 | ||
62 | if (cds_list_empty(&allocator->unused_list)) { | |
63 | if (allocator->position >= allocator->size) { | |
64 | /* No indices left. */ | |
65 | status = LTTNG_INDEX_ALLOCATOR_STATUS_EMPTY; | |
66 | goto end; | |
67 | } | |
68 | ||
69 | *allocated_index = allocator->position++; | |
70 | } else { | |
71 | struct lttng_index *index; | |
72 | ||
73 | index = cds_list_first_entry(&allocator->unused_list, | |
74 | typeof(*index), head); | |
75 | cds_list_del(&index->head); | |
76 | *allocated_index = index->index; | |
77 | free(index); | |
78 | } | |
79 | ||
80 | end: | |
81 | return status; | |
82 | } | |
83 | ||
84 | enum lttng_index_allocator_status lttng_index_allocator_release( | |
85 | struct lttng_index_allocator *allocator, uint64_t idx) | |
86 | { | |
87 | struct lttng_index *index = NULL; | |
88 | enum lttng_index_allocator_status status = | |
89 | LTTNG_INDEX_ALLOCATOR_STATUS_OK; | |
90 | ||
91 | assert(idx < allocator->size); | |
92 | ||
93 | index = zmalloc(sizeof(*index)); | |
94 | if (!index) { | |
95 | PERROR("Failed to allocate free index queue"); | |
96 | status = LTTNG_INDEX_ALLOCATOR_STATUS_ERROR; | |
97 | goto end; | |
98 | } | |
99 | ||
100 | index->index = idx; | |
101 | cds_list_add_tail(&index->head, &allocator->unused_list); | |
102 | ||
103 | end: | |
104 | return status; | |
105 | } | |
106 | ||
107 | void lttng_index_allocator_destroy(struct lttng_index_allocator *allocator) | |
108 | { | |
109 | struct lttng_index *index = NULL, *tmp_index = NULL; | |
110 | ||
111 | if (!allocator) { | |
112 | return; | |
113 | } | |
114 | ||
115 | if (lttng_index_allocator_get_index_count(allocator) > 0) { | |
116 | WARN("Destroying index allocator with %" PRIu64 | |
117 | " slot indexes still in use", | |
118 | lttng_index_allocator_get_index_count(allocator)); | |
119 | } | |
120 | ||
121 | cds_list_for_each_entry_safe(index, tmp_index, | |
122 | &allocator->unused_list, head) { | |
123 | cds_list_del(&index->head); | |
124 | free(index); | |
125 | } | |
126 | ||
127 | free(allocator); | |
128 | } |