projects / lttng-modules.git / blame
| Commit | Line | Data |
|---|---|---|
| 9f36eaed MJ |
1 | /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1) |
| 2 | * | |
| 2754583e MD |
3 | * lttng-clock.c |
| 4 | * | |
| 5 | * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
| 2754583e MD |
6 | */ |
| 7 | ||
| 8 | #include <linux/module.h> | |
| 9 | #include <linux/kmod.h> | |
| 10 | #include <linux/mutex.h> | |
| 11 | ||
| 241ae9a8 MD |
12 | #include <wrapper/trace-clock.h> |
| 13 | #include <lttng-events.h> | |
| 14 | #include <lttng-tracer.h> | |
| 2754583e MD |
15 | |
| 16 | struct lttng_trace_clock *lttng_trace_clock; | |
| 17 | EXPORT_SYMBOL_GPL(lttng_trace_clock); | |
| 18 | ||
| 19 | static DEFINE_MUTEX(clock_mutex); | |
| 20 | static struct module *lttng_trace_clock_mod; /* plugin */ | |
| 21 | static int clock_used; /* refcount */ | |
| 22 | ||
| 23 | int lttng_clock_register_plugin(struct lttng_trace_clock *ltc, | |
| 24 | struct module *mod) | |
| 25 | { | |
| 26 | int ret = 0; | |
| 27 | ||
| 28 | mutex_lock(&clock_mutex); | |
| 29 | if (clock_used) { | |
| 30 | ret = -EBUSY; | |
| 31 | goto end; | |
| 32 | } | |
| 33 | if (lttng_trace_clock_mod) { | |
| 34 | ret = -EEXIST; | |
| 35 | goto end; | |
| 36 | } | |
| 37 | /* set clock */ | |
| a8f2d0c7 | 38 | WRITE_ONCE(lttng_trace_clock, ltc); |
| 2754583e MD |
39 | lttng_trace_clock_mod = mod; |
| 40 | end: | |
| 41 | mutex_unlock(&clock_mutex); | |
| 42 | return ret; | |
| 43 | } | |
| 44 | EXPORT_SYMBOL_GPL(lttng_clock_register_plugin); | |
| 45 | ||
| 46 | void lttng_clock_unregister_plugin(struct lttng_trace_clock *ltc, | |
| 47 | struct module *mod) | |
| 48 | { | |
| 49 | mutex_lock(&clock_mutex); | |
| 50 | WARN_ON_ONCE(clock_used); | |
| 51 | if (!lttng_trace_clock_mod) { | |
| 52 | goto end; | |
| 53 | } | |
| 54 | WARN_ON_ONCE(lttng_trace_clock_mod != mod); | |
| 55 | ||
| a8f2d0c7 | 56 | WRITE_ONCE(lttng_trace_clock, NULL); |
| 2754583e MD |
57 | lttng_trace_clock_mod = NULL; |
| 58 | end: | |
| 59 | mutex_unlock(&clock_mutex); | |
| 60 | } | |
| 61 | EXPORT_SYMBOL_GPL(lttng_clock_unregister_plugin); | |
| 62 | ||
| 63 | void lttng_clock_ref(void) | |
| 64 | { | |
| 65 | mutex_lock(&clock_mutex); | |
| 66 | clock_used++; | |
| 67 | if (lttng_trace_clock_mod) { | |
| 68 | int ret; | |
| 69 | ||
| 70 | ret = try_module_get(lttng_trace_clock_mod); | |
| 71 | if (!ret) { | |
| 72 | printk(KERN_ERR "LTTng-clock cannot get clock plugin module\n"); | |
| a8f2d0c7 | 73 | WRITE_ONCE(lttng_trace_clock, NULL); |
| 2754583e MD |
74 | lttng_trace_clock_mod = NULL; |
| 75 | } | |
| 76 | } | |
| 77 | mutex_unlock(&clock_mutex); | |
| 78 | } | |
| 79 | EXPORT_SYMBOL_GPL(lttng_clock_ref); | |
| 80 | ||
| 81 | void lttng_clock_unref(void) | |
| 82 | { | |
| 83 | mutex_lock(&clock_mutex); | |
| 84 | clock_used--; | |
| 85 | if (lttng_trace_clock_mod) | |
| 86 | module_put(lttng_trace_clock_mod); | |
| 87 | mutex_unlock(&clock_mutex); | |
| 88 | } | |
| 89 | EXPORT_SYMBOL_GPL(lttng_clock_unref); | |
| 90 | ||
| 91 | MODULE_LICENSE("GPL and additional rights"); | |
| 92 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); | |
| 93 | MODULE_DESCRIPTION("LTTng Clock"); | |
| 94 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." | |
| 95 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
| 96 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
| 97 | LTTNG_MODULES_EXTRAVERSION); |