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| 2 | |
| 3 | * Copyright 2023 Red Hat
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| 4 |
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| 5 |
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| 6 | #include "thread-utils.h"
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| 7 |
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| 8 | #include <asm/current.h>
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| 9 | #include <linux/delay.h>
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| 10 | #include <linux/kthread.h>
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| 11 | #include <linux/mutex.h>
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| 12 | #include <linux/types.h>
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| 13 |
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| 14 | #include "errors.h"
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| 15 | #include "logger.h"
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| 16 | #include "memory-alloc.h"
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| 17 |
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| 18 | static struct hlist_head thread_list;
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| 19 | static struct mutex thread_mutex;
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| 20 |
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| 21 | struct thread {
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| 22 | void (*thread_function)(void *thread_data);
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| 23 | void *thread_data;
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| 24 | struct hlist_node thread_links;
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| 25 | struct task_struct *thread_task;
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| 26 | struct completion thread_done;
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| 27 | };
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| 28 |
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| 29 | void vdo_initialize_threads_mutex(void)
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| 30 | {
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| 31 | mutex_init(&thread_mutex);
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| 32 | }
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| 33 |
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| 34 | static int thread_starter(void *arg)
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| 35 | {
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| 36 | struct registered_thread allocating_thread;
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| 37 | struct thread *thread = arg;
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| 38 |
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| 39 | thread->thread_task = current;
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| 40 | mutex_lock(&thread_mutex);
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| 41 | hlist_add_head(&thread->thread_links, &thread_list);
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| 42 | mutex_unlock(&thread_mutex);
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| 43 | vdo_register_allocating_thread(&allocating_thread, NULL);
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| 44 | thread->thread_function(thread->thread_data);
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| 45 | vdo_unregister_allocating_thread();
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| 46 | complete(&thread->thread_done);
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| 47 | return 0;
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| 48 | }
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| 49 |
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| 50 | int vdo_create_thread(void (*thread_function)(void *), void *thread_data,
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| 51 | const char *name, struct thread **new_thread)
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| 52 | {
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| 53 | char *name_colon = strchr(name, ':');
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| 54 | char *my_name_colon = strchr(current->comm, ':');
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| 55 | struct task_struct *task;
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| 56 | struct thread *thread;
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| 57 | int result;
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| 58 |
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| 59 | result = vdo_allocate(1, __func__, &thread);
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| 60 | if (result != VDO_SUCCESS) {
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| 61 | vdo_log_warning("Error allocating memory for %s", name);
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| 62 | return result;
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| 63 | }
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| 64 |
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| 65 | thread->thread_function = thread_function;
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| 66 | thread->thread_data = thread_data;
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| 67 | init_completion(&thread->thread_done);
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| 68 | |
| 69 | * Start the thread, with an appropriate thread name.
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| 70 | *
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| 71 | * If the name supplied contains a colon character, use that name. This causes uds module
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| 72 | * threads to have names like "uds:callbackW" and the main test runner thread to be named
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| 73 | * "zub:runtest".
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| 74 | *
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| 75 | * Otherwise if the current thread has a name containing a colon character, prefix the name
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| 76 | * supplied with the name of the current thread up to (and including) the colon character.
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| 77 | * Thus when the "kvdo0:dedupeQ" thread opens an index session, all the threads associated
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| 78 | * with that index will have names like "kvdo0:foo".
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| 79 | *
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| 80 | * Otherwise just use the name supplied. This should be a rare occurrence.
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| 81 |
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| 82 | if ((name_colon == NULL) && (my_name_colon != NULL)) {
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| 83 | task = kthread_run(thread_starter, thread, "%.*s:%s",
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| 84 | (int) (my_name_colon - current->comm), current->comm,
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| 85 | name);
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| 86 | } else {
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| 87 | task = kthread_run(thread_starter, thread, "%s", name);
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| 88 | }
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| 89 |
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| 90 | if (IS_ERR(task)) {
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| 91 | vdo_free(thread);
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| 92 | return PTR_ERR(task);
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| 93 | }
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| 94 |
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| 95 | *new_thread = thread;
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| 96 | return VDO_SUCCESS;
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| 97 | }
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| 98 |
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| 99 | void vdo_join_threads(struct thread *thread)
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| 100 | {
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| 101 | while (wait_for_completion_interruptible(&thread->thread_done))
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| 102 | fsleep(1000);
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| 103 |
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| 104 | mutex_lock(&thread_mutex);
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| 105 | hlist_del(&thread->thread_links);
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| 106 | mutex_unlock(&thread_mutex);
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| 107 | vdo_free(thread);
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| 108 | }
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