Migrate tracepoint instrumentation to TP_FIELDS

[lttng-modules.git] / lttng-context-ppid.c

diff --git a/lttng-context-ppid.c b/lttng-context-ppid.c
index a22c9d83ccd2671133db528ea8b02b64ef242620..33ea1a796e0503d203b64cbd74db7420cb3fb534 100644 (file)
--- a/lttng-context-ppid.c
+++ b/lttng-context-ppid.c
@@ -46,7 +46,6 @@ void ppid_record(struct lttng_ctx_field *field,
 {
        pid_t ppid;
 
-
        /*
         * TODO: when we eventually add RCU subsystem instrumentation,
         * taking the rcu read lock here will trigger RCU tracing
@@ -54,7 +53,6 @@ void ppid_record(struct lttng_ctx_field *field,
         * it synchronizes both for RCU and RCU sched, and rely on
         * rcu_read_lock_sched_notrace.
         */
-
        rcu_read_lock();
        ppid = task_tgid_nr(current->real_parent);
        rcu_read_unlock();
@@ -62,6 +60,25 @@ void ppid_record(struct lttng_ctx_field *field,
        chan->ops->event_write(ctx, &ppid, sizeof(ppid));
 }
 
+static
+void ppid_get_value(struct lttng_ctx_field *field,
+               union lttng_ctx_value *value)
+{
+       pid_t ppid;
+
+       /*
+        * TODO: when we eventually add RCU subsystem instrumentation,
+        * taking the rcu read lock here will trigger RCU tracing
+        * recursively. We should modify the kernel synchronization so
+        * it synchronizes both for RCU and RCU sched, and rely on
+        * rcu_read_lock_sched_notrace.
+        */
+       rcu_read_lock();
+       ppid = task_tgid_nr(current->real_parent);
+       rcu_read_unlock();
+       value->s64 = ppid;
+}
+
 int lttng_add_ppid_to_ctx(struct lttng_ctx **ctx)
 {
        struct lttng_ctx_field *field;
@@ -83,6 +100,7 @@ int lttng_add_ppid_to_ctx(struct lttng_ctx **ctx)
        field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
        field->get_size = ppid_get_size;
        field->record = ppid_record;
+       field->get_value = ppid_get_value;
        lttng_context_update(*ctx);
        wrapper_vmalloc_sync_all();
        return 0;