*/
#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h> /* For vmalloc_sync_all */
#include "ltt-events.h"
static LIST_HEAD(sessions);
+static LIST_HEAD(ltt_transport_list);
static DEFINE_MUTEX(sessions_mutex);
static struct kmem_cache *event_cache;
struct ltt_session *session;
mutex_lock(&sessions_mutex);
- session = kmalloc(sizeof(struct ltt_session));
+ session = kmalloc(sizeof(struct ltt_session), GFP_KERNEL);
if (!session)
return NULL;
INIT_LIST_HEAD(&session->chan);
list_add(&session->list, &sessions);
mutex_unlock(&sessions_mutex);
return session;
-
-exist:
- mutex_unlock(&sessions_mutex);
- return NULL;
}
-int ltt_session_destroy(struct ltt_session *session)
+void ltt_session_destroy(struct ltt_session *session)
{
struct ltt_channel *chan, *tmpchan;
struct ltt_event *event, *tmpevent;
kfree(session);
}
+int ltt_session_start(struct ltt_session *session)
+{
+ int ret = 0;
+
+ mutex_lock(&sessions_mutex);
+ if (session->active) {
+ ret = -EBUSY;
+ goto end;
+ }
+ session->active = 1;
+ synchronize_trace(); /* Wait for in-flight events to complete */
+end:
+ mutex_unlock(&sessions_mutex);
+ return ret;
+}
+
+int ltt_session_stop(struct ltt_session *session)
+{
+ int ret = 0;
+
+ mutex_lock(&sessions_mutex);
+ if (!session->active) {
+ ret = -EBUSY;
+ goto end;
+ }
+ session->active = 0;
+ synchronize_trace(); /* Wait for in-flight events to complete */
+end:
+ mutex_unlock(&sessions_mutex);
+ return ret;
+}
+
struct ltt_channel *ltt_channel_create(struct ltt_session *session,
int overwrite, void *buf_addr,
size_t subbuf_size, size_t num_subbuf,
unsigned int read_timer_interval)
{
struct ltt_channel *chan;
+ struct ltt_transport *transport = NULL, *tran_iter;
+ char *transport_name;
mutex_lock(&sessions_mutex);
if (session->active)
goto active; /* Refuse to add channel to active session */
+ transport_name = overwrite ? "relay-overwrite" : "relay-discard";
+ list_for_each_entry(tran_iter, <t_transport_list, node) {
+ if (!strcmp(tran_iter->name, transport_name)) {
+ transport = tran_iter;
+ break;
+ }
+ }
+ if (!transport)
+ goto notransport;
chan = kmalloc(sizeof(struct ltt_channel), GFP_KERNEL);
if (!chan)
- return NULL;
+ goto nomem;
chan->session = session;
init_waitqueue_head(&chan->notify_wait);
-
- /* TODO: create rb channel */
+ chan->chan = transport->ops.channel_create("[lttng]", session, buf_addr,
+ subbuf_size, num_subbuf, switch_timer_interval,
+ read_timer_interval);
+ chan->ops = &transport->ops;
list_add(&chan->list, &session->chan);
mutex_unlock(&sessions_mutex);
return chan;
-exist:
+nomem:
+notransport:
active:
mutex_unlock(&sessions_mutex);
return NULL;
/*
* Only used internally at session destruction.
*/
-int _ltt_channel_destroy(struct ltt_channel *chan)
+void _ltt_channel_destroy(struct ltt_channel *chan)
{
- /* TODO: destroy rb channel */
+ chan->ops->channel_destroy(chan->chan);
list_del(&chan->list);
kfree(chan);
}
list_for_each_entry(event, &chan->session->events, list)
if (!strcmp(event->name, name))
goto exist;
- event = kmem_cache_zalloc(events_cache, GFP_KERNEL);
+ event = kmem_cache_zalloc(event_cache, GFP_KERNEL);
if (!event)
goto cache_error;
event->name = kmalloc(strlen(name) + 1, GFP_KERNEL);
if (!event->name)
- goto error;
+ goto name_error;
strcpy(event->name, name);
event->chan = chan;
event->probe = probe;
event->filter = filter;
event->id = chan->free_event_id++;
event->itype = itype;
- mutex_unlock(&sessions_mutex);
/* Populate ltt_event structure before tracepoint registration. */
smp_wmb();
switch (itype) {
case INSTRUM_TRACEPOINTS:
ret = tracepoint_probe_register(name, probe, event);
+ if (ret)
+ goto register_error;
break;
default:
WARN_ON_ONCE(1);
}
+ mutex_unlock(&sessions_mutex);
return event;
-error:
- kmem_cache_free(event);
+register_error:
+ kfree(event->name);
+name_error:
+ kmem_cache_free(event_cache, event);
cache_error:
exist:
full:
*/
int _ltt_event_destroy(struct ltt_event *event)
{
+ int ret = -EINVAL;
+
switch (event->itype) {
case INSTRUM_TRACEPOINTS:
- ret = tracepoint_probe_unregister(name, event->probe, event);
+ ret = tracepoint_probe_unregister(event->name, event->probe,
+ event);
+ if (ret)
+ return ret;
break;
default:
WARN_ON_ONCE(1);
}
kfree(event->name);
- kmem_cache_free(event);
+ kmem_cache_free(event_cache, event);
+ return ret;
}
-static int __init ltt_events_init(void)
+/**
+ * ltt_transport_register - LTT transport registration
+ * @transport: transport structure
+ *
+ * Registers a transport which can be used as output to extract the data out of
+ * LTTng. The module calling this registration function must ensure that no
+ * trap-inducing code will be executed by the transport functions. E.g.
+ * vmalloc_sync_all() must be called between a vmalloc and the moment the memory
+ * is made visible to the transport function. This registration acts as a
+ * vmalloc_sync_all. Therefore, only if the module allocates virtual memory
+ * after its registration must it synchronize the TLBs.
+ */
+void ltt_transport_register(struct ltt_transport *transport)
{
- int ret;
+ /*
+ * Make sure no page fault can be triggered by the module about to be
+ * registered. We deal with this here so we don't have to call
+ * vmalloc_sync_all() in each module's init.
+ */
+ vmalloc_sync_all();
- events_cache = KMEM_CACHE(ltt_event, 0);
- if (!events_cache)
- return -ENOMEM;
+ mutex_lock(&sessions_mutex);
+ list_add_tail(&transport->node, <t_transport_list);
+ mutex_unlock(&sessions_mutex);
+}
+EXPORT_SYMBOL_GPL(ltt_transport_register);
+
+/**
+ * ltt_transport_unregister - LTT transport unregistration
+ * @transport: transport structure
+ */
+void ltt_transport_unregister(struct ltt_transport *transport)
+{
+ mutex_lock(&sessions_mutex);
+ list_del(&transport->node);
+ mutex_unlock(&sessions_mutex);
+}
+EXPORT_SYMBOL_GPL(ltt_transport_unregister);
- /* TODO: show ABI to userspace */
+static int __init ltt_events_init(void)
+{
+ event_cache = KMEM_CACHE(ltt_event, 0);
+ if (!event_cache)
+ return -ENOMEM;
return 0;
}
+module_init(ltt_events_init);
+
static void __exit ltt_events_exit(void)
{
struct ltt_session *session, *tmpsession;
- /* TODO: hide ABI from userspace, wait for callers to release refs. */
-
list_for_each_entry_safe(session, tmpsession, &sessions, list)
ltt_session_destroy(session);
- kmem_cache_destroy(events_cache);
+ kmem_cache_destroy(event_cache);
}
+module_exit(ltt_events_exit);
+
MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
MODULE_DESCRIPTION("LTTng Events");
projects / lttng-modules.git / blobdiff