| 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 <inttypes.h> |
| 9 | |
| 10 | #include <urcu.h> |
| 11 | #include <urcu/list.h> |
| 12 | |
| 13 | #include "macros.h" |
| 14 | #include "error.h" |
| 15 | |
| 16 | #include "index-allocator.h" |
| 17 | |
| 18 | struct lttng_index_allocator { |
| 19 | struct cds_list_head unused_list; |
| 20 | uint64_t size; |
| 21 | uint64_t position; |
| 22 | uint64_t nb_allocated_indexes; |
| 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 = (lttng_index_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 | allocator->nb_allocated_indexes = 0; |
| 44 | |
| 45 | CDS_INIT_LIST_HEAD(&allocator->unused_list); |
| 46 | |
| 47 | end: |
| 48 | return allocator; |
| 49 | } |
| 50 | |
| 51 | uint64_t lttng_index_allocator_get_index_count(struct lttng_index_allocator *allocator) |
| 52 | { |
| 53 | return allocator->nb_allocated_indexes; |
| 54 | } |
| 55 | |
| 56 | enum lttng_index_allocator_status lttng_index_allocator_alloc( |
| 57 | struct lttng_index_allocator *allocator, |
| 58 | uint64_t *allocated_index) |
| 59 | { |
| 60 | enum lttng_index_allocator_status status = |
| 61 | LTTNG_INDEX_ALLOCATOR_STATUS_OK; |
| 62 | |
| 63 | if (cds_list_empty(&allocator->unused_list)) { |
| 64 | if (allocator->position >= allocator->size) { |
| 65 | /* No indices left. */ |
| 66 | status = LTTNG_INDEX_ALLOCATOR_STATUS_EMPTY; |
| 67 | goto end; |
| 68 | } |
| 69 | |
| 70 | *allocated_index = allocator->position++; |
| 71 | } else { |
| 72 | struct lttng_index *index; |
| 73 | |
| 74 | index = cds_list_first_entry(&allocator->unused_list, |
| 75 | typeof(*index), head); |
| 76 | cds_list_del(&index->head); |
| 77 | *allocated_index = index->index; |
| 78 | free(index); |
| 79 | } |
| 80 | |
| 81 | allocator->nb_allocated_indexes++; |
| 82 | end: |
| 83 | return status; |
| 84 | } |
| 85 | |
| 86 | enum lttng_index_allocator_status lttng_index_allocator_release( |
| 87 | struct lttng_index_allocator *allocator, uint64_t idx) |
| 88 | { |
| 89 | struct lttng_index *index = NULL; |
| 90 | enum lttng_index_allocator_status status = |
| 91 | LTTNG_INDEX_ALLOCATOR_STATUS_OK; |
| 92 | |
| 93 | LTTNG_ASSERT(idx < allocator->size); |
| 94 | |
| 95 | index = (lttng_index *) zmalloc(sizeof(*index)); |
| 96 | if (!index) { |
| 97 | PERROR("Failed to allocate free index queue"); |
| 98 | status = LTTNG_INDEX_ALLOCATOR_STATUS_ERROR; |
| 99 | goto end; |
| 100 | } |
| 101 | |
| 102 | index->index = idx; |
| 103 | cds_list_add_tail(&index->head, &allocator->unused_list); |
| 104 | allocator->nb_allocated_indexes--; |
| 105 | |
| 106 | end: |
| 107 | return status; |
| 108 | } |
| 109 | |
| 110 | void lttng_index_allocator_destroy(struct lttng_index_allocator *allocator) |
| 111 | { |
| 112 | struct lttng_index *index = NULL, *tmp_index = NULL; |
| 113 | |
| 114 | if (!allocator) { |
| 115 | return; |
| 116 | } |
| 117 | |
| 118 | if (lttng_index_allocator_get_index_count(allocator) > 0) { |
| 119 | WARN("Destroying index allocator with %" PRIu64 |
| 120 | " slot indexes still in use", |
| 121 | lttng_index_allocator_get_index_count(allocator)); |
| 122 | } |
| 123 | |
| 124 | cds_list_for_each_entry_safe(index, tmp_index, |
| 125 | &allocator->unused_list, head) { |
| 126 | cds_list_del(&index->head); |
| 127 | free(index); |
| 128 | } |
| 129 | |
| 130 | free(allocator); |
| 131 | } |