| 1 | // SPDX-License-Identifier: LGPL-2.1-or-later |
| 2 | /* |
| 3 | * Copyright (C) 2020-2021 Paul Cercueil <paul@crapouillou.net> |
| 4 | */ |
| 5 | |
| 6 | #include "blockcache.h" |
| 7 | #include "debug.h" |
| 8 | #include "lightrec-private.h" |
| 9 | #include "memmanager.h" |
| 10 | #include "slist.h" |
| 11 | #include "reaper.h" |
| 12 | |
| 13 | #include <errno.h> |
| 14 | #include <pthread.h> |
| 15 | #include <stdatomic.h> |
| 16 | #include <stdbool.h> |
| 17 | |
| 18 | struct reaper_elm { |
| 19 | reap_func_t func; |
| 20 | void *data; |
| 21 | struct slist_elm slist; |
| 22 | }; |
| 23 | |
| 24 | struct reaper { |
| 25 | struct lightrec_state *state; |
| 26 | pthread_mutex_t mutex; |
| 27 | struct slist_elm reap_list; |
| 28 | |
| 29 | atomic_uint sem; |
| 30 | }; |
| 31 | |
| 32 | struct reaper *lightrec_reaper_init(struct lightrec_state *state) |
| 33 | { |
| 34 | struct reaper *reaper; |
| 35 | int ret; |
| 36 | |
| 37 | reaper = lightrec_malloc(state, MEM_FOR_LIGHTREC, sizeof(*reaper)); |
| 38 | if (!reaper) { |
| 39 | pr_err("Cannot create reaper: Out of memory\n"); |
| 40 | return NULL; |
| 41 | } |
| 42 | |
| 43 | reaper->state = state; |
| 44 | reaper->sem = 0; |
| 45 | slist_init(&reaper->reap_list); |
| 46 | |
| 47 | ret = pthread_mutex_init(&reaper->mutex, NULL); |
| 48 | if (ret) { |
| 49 | pr_err("Cannot init mutex variable: %d\n", ret); |
| 50 | lightrec_free(reaper->state, MEM_FOR_LIGHTREC, |
| 51 | sizeof(*reaper), reaper); |
| 52 | return NULL; |
| 53 | } |
| 54 | |
| 55 | return reaper; |
| 56 | } |
| 57 | |
| 58 | void lightrec_reaper_destroy(struct reaper *reaper) |
| 59 | { |
| 60 | pthread_mutex_destroy(&reaper->mutex); |
| 61 | lightrec_free(reaper->state, MEM_FOR_LIGHTREC, sizeof(*reaper), reaper); |
| 62 | } |
| 63 | |
| 64 | int lightrec_reaper_add(struct reaper *reaper, reap_func_t f, void *data) |
| 65 | { |
| 66 | struct reaper_elm *reaper_elm; |
| 67 | struct slist_elm *elm; |
| 68 | int ret = 0; |
| 69 | |
| 70 | pthread_mutex_lock(&reaper->mutex); |
| 71 | |
| 72 | for (elm = reaper->reap_list.next; elm; elm = elm->next) { |
| 73 | reaper_elm = container_of(elm, struct reaper_elm, slist); |
| 74 | |
| 75 | if (reaper_elm->data == data) |
| 76 | goto out_unlock; |
| 77 | } |
| 78 | |
| 79 | reaper_elm = lightrec_malloc(reaper->state, MEM_FOR_LIGHTREC, |
| 80 | sizeof(*reaper_elm)); |
| 81 | if (!reaper_elm) { |
| 82 | pr_err("Cannot add reaper entry: Out of memory\n"); |
| 83 | ret = -ENOMEM; |
| 84 | goto out_unlock; |
| 85 | } |
| 86 | |
| 87 | reaper_elm->func = f; |
| 88 | reaper_elm->data = data; |
| 89 | slist_append(&reaper->reap_list, &reaper_elm->slist); |
| 90 | |
| 91 | out_unlock: |
| 92 | pthread_mutex_unlock(&reaper->mutex); |
| 93 | return ret; |
| 94 | } |
| 95 | |
| 96 | static bool lightrec_reaper_can_reap(struct reaper *reaper) |
| 97 | { |
| 98 | return !atomic_load_explicit(&reaper->sem, memory_order_relaxed); |
| 99 | } |
| 100 | |
| 101 | void lightrec_reaper_reap(struct reaper *reaper) |
| 102 | { |
| 103 | struct reaper_elm *reaper_elm; |
| 104 | struct slist_elm *elm; |
| 105 | |
| 106 | pthread_mutex_lock(&reaper->mutex); |
| 107 | |
| 108 | while (lightrec_reaper_can_reap(reaper) && |
| 109 | !!(elm = slist_first(&reaper->reap_list))) { |
| 110 | slist_remove(&reaper->reap_list, elm); |
| 111 | pthread_mutex_unlock(&reaper->mutex); |
| 112 | |
| 113 | reaper_elm = container_of(elm, struct reaper_elm, slist); |
| 114 | |
| 115 | (*reaper_elm->func)(reaper->state, reaper_elm->data); |
| 116 | |
| 117 | lightrec_free(reaper->state, MEM_FOR_LIGHTREC, |
| 118 | sizeof(*reaper_elm), reaper_elm); |
| 119 | |
| 120 | pthread_mutex_lock(&reaper->mutex); |
| 121 | } |
| 122 | |
| 123 | pthread_mutex_unlock(&reaper->mutex); |
| 124 | } |
| 125 | |
| 126 | void lightrec_reaper_pause(struct reaper *reaper) |
| 127 | { |
| 128 | atomic_fetch_add_explicit(&reaper->sem, 1, memory_order_relaxed); |
| 129 | } |
| 130 | |
| 131 | void lightrec_reaper_continue(struct reaper *reaper) |
| 132 | { |
| 133 | atomic_fetch_sub_explicit(&reaper->sem, 1, memory_order_relaxed); |
| 134 | } |