[RFC patch 20/41] Linux Kernel Markers - Iterator

[Mathieu Desnoyers]

Add marker iterators. Useful for /proc interface (listing markers).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
---
 include/linux/marker.h |   12 ++++++++
 include/linux/module.h |    6 ++++
 kernel/marker.c        |   70 +++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/module.c        |   32 ++++++++++++++++++++++
 4 files changed, 120 insertions(+)

Index: linux-2.6-lttng/kernel/marker.c
===================================================================
--- linux-2.6-lttng.orig/kernel/marker.c	2009-03-05 15:21:58.000000000 -0500
+++ linux-2.6-lttng/kernel/marker.c	2009-03-05 15:45:38.000000000 -0500
@@ -898,6 +898,76 @@ EXPORT_SYMBOL_GPL(marker_get_private_dat
 
 #ifdef CONFIG_MODULES
 
+/**
+ * marker_get_iter_range - Get a next marker iterator given a range.
+ * @marker: current markers (in), next marker (out)
+ * @begin: beginning of the range
+ * @end: end of the range
+ *
+ * Returns whether a next marker has been found (1) or not (0).
+ * Will return the first marker in the range if the input marker is NULL.
+ */
+int marker_get_iter_range(struct marker **marker, struct marker *begin,
+	struct marker *end)
+{
+	if (!*marker && begin != end) {
+		*marker = begin;
+		return 1;
+	}
+	if (*marker >= begin && *marker < end)
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(marker_get_iter_range);
+
+static void marker_get_iter(struct marker_iter *iter)
+{
+	int found = 0;
+
+	/* Core kernel markers */
+	if (!iter->module) {
+		found = marker_get_iter_range(&iter->marker,
+				__start___markers, __stop___markers);
+		if (found)
+			goto end;
+	}
+	/* Markers in modules. */
+	found = module_get_iter_markers(iter);
+end:
+	if (!found)
+		marker_iter_reset(iter);
+}
+
+void marker_iter_start(struct marker_iter *iter)
+{
+	marker_get_iter(iter);
+}
+EXPORT_SYMBOL_GPL(marker_iter_start);
+
+void marker_iter_next(struct marker_iter *iter)
+{
+	iter->marker++;
+	/*
+	 * iter->marker may be invalid because we blindly incremented it.
+	 * Make sure it is valid by marshalling on the markers, getting the
+	 * markers from following modules if necessary.
+	 */
+	marker_get_iter(iter);
+}
+EXPORT_SYMBOL_GPL(marker_iter_next);
+
+void marker_iter_stop(struct marker_iter *iter)
+{
+}
+EXPORT_SYMBOL_GPL(marker_iter_stop);
+
+void marker_iter_reset(struct marker_iter *iter)
+{
+	iter->module = NULL;
+	iter->marker = NULL;
+}
+EXPORT_SYMBOL_GPL(marker_iter_reset);
+
 int marker_module_notify(struct notifier_block *self,
 			 unsigned long val, void *data)
 {
Index: linux-2.6-lttng/kernel/module.c
===================================================================
--- linux-2.6-lttng.orig/kernel/module.c	2009-03-05 15:45:37.000000000 -0500
+++ linux-2.6-lttng/kernel/module.c	2009-03-05 15:45:38.000000000 -0500
@@ -2814,6 +2814,38 @@ void module_update_markers(void)
 				mod->markers + mod->num_markers);
 	mutex_unlock(&module_mutex);
 }
+
+/*
+ * Returns 0 if current not found.
+ * Returns 1 if current found.
+ */
+int module_get_iter_markers(struct marker_iter *iter)
+{
+	struct module *iter_mod;
+	int found = 0;
+
+	mutex_lock(&module_mutex);
+	list_for_each_entry(iter_mod, &modules, list) {
+		if (!iter_mod->taints) {
+			/*
+			 * Sorted module list
+			 */
+			if (iter_mod < iter->module)
+				continue;
+			else if (iter_mod > iter->module)
+				iter->marker = NULL;
+			found = marker_get_iter_range(&iter->marker,
+				iter_mod->markers,
+				iter_mod->markers + iter_mod->num_markers);
+			if (found) {
+				iter->module = iter_mod;
+				break;
+			}
+		}
+	}
+	mutex_unlock(&module_mutex);
+	return found;
+}
 #endif
 
 #ifdef CONFIG_TRACEPOINTS
Index: linux-2.6-lttng/include/linux/marker.h
===================================================================
--- linux-2.6-lttng.orig/include/linux/marker.h	2009-03-05 15:21:58.000000000 -0500
+++ linux-2.6-lttng/include/linux/marker.h	2009-03-05 15:45:38.000000000 -0500
@@ -218,4 +218,16 @@ extern void *marker_get_private_data(con
  */
 #define marker_synchronize_unregister() synchronize_sched()
 
+struct marker_iter {
+	struct module *module;
+	struct marker *marker;
+};
+
+extern void marker_iter_start(struct marker_iter *iter);
+extern void marker_iter_next(struct marker_iter *iter);
+extern void marker_iter_stop(struct marker_iter *iter);
+extern void marker_iter_reset(struct marker_iter *iter);
+extern int marker_get_iter_range(struct marker **marker, struct marker *begin,
+	struct marker *end);
+
 #endif
Index: linux-2.6-lttng/include/linux/module.h
===================================================================
--- linux-2.6-lttng.orig/include/linux/module.h	2009-03-05 15:21:58.000000000 -0500
+++ linux-2.6-lttng/include/linux/module.h	2009-03-05 15:45:38.000000000 -0500
@@ -472,6 +472,7 @@ int unregister_module_notifier(struct no
 extern void print_modules(void);
 
 extern void module_update_markers(void);
+extern int module_get_iter_markers(struct marker_iter *iter);
 
 extern void module_update_tracepoints(void);
 extern int module_get_iter_tracepoints(struct tracepoint_iter *iter);
@@ -589,6 +590,11 @@ static inline int module_get_iter_tracep
 	return 0;
 }
 
+static inline int module_get_iter_markers(struct marker_iter *iter)
+{
+	return 0;
+}
+
 #endif /* CONFIG_MODULES */
 
 struct device_driver;

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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