X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lttng-context-vppid.c;h=80b1f9e7a20222f3e232e1089023abb839fbee58;hb=refs%2Fheads%2Fstable-2.7;hp=365d97394e89c98094b43dacc5918ee353271c00;hpb=de544ea58e0231054bb62e2c814c662b894d6e25;p=lttng-modules.git

diff --git a/lttng-context-vppid.c b/lttng-context-vppid.c
index 365d9739..80b1f9e7 100644
--- a/lttng-context-vppid.c
+++ b/lttng-context-vppid.c
@@ -51,6 +51,15 @@ void vppid_record(struct lttng_ctx_field *field,
 	 * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
 	 * the current thread nsproxy to perform the lookup.
 	 */
+
+	/*
+	 * 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();
 	parent = rcu_dereference(current->real_parent);
 	if (!current->nsproxy)
@@ -62,6 +71,36 @@ void vppid_record(struct lttng_ctx_field *field,
 	chan->ops->event_write(ctx, &vppid, sizeof(vppid));
 }
 
+static
+void vppid_get_value(struct lttng_ctx_field *field,
+		union lttng_ctx_value *value)
+{
+	struct task_struct *parent;
+	pid_t vppid;
+
+	/*
+	 * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
+	 * the current thread nsproxy to perform the lookup.
+	 */
+
+	/*
+	 * 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();
+	parent = rcu_dereference(current->real_parent);
+	if (!current->nsproxy)
+		vppid = 0;
+	else
+		vppid = task_tgid_vnr(parent);
+	rcu_read_unlock();
+	value->s64 = vppid;
+}
+
 int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
 {
 	struct lttng_ctx_field *field;
@@ -77,17 +116,15 @@ int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
 	field->event_field.type.atype = atype_integer;
 	field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
 	field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
-	field->event_field.type.u.basic.integer.signedness = is_signed_type(pid_t);
+	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
 	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
 	field->event_field.type.u.basic.integer.base = 10;
 	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
 	field->get_size = vppid_get_size;
 	field->record = vppid_record;
+	field->get_value = vppid_get_value;
+	lttng_context_update(*ctx);
 	wrapper_vmalloc_sync_all();
 	return 0;
 }
 EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Linux Trace Toolkit vPPID Context");