[PATCH v2 07/14] perf, persistent: Introduce get_persistent_event()

[Robert Richter <rric@kernel.org>]

From: Robert Richter <robert.richter@linaro.org>

Reducing duplicate code by introducing function get_persistent_event()
to get the descriptor of an persistent event.

Signed-off-by: Robert Richter <robert.richter@linaro.org>
Signed-off-by: Robert Richter <rric@kernel.org>
---
 kernel/events/persistent.c | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/kernel/events/persistent.c b/kernel/events/persistent.c
index e6a7664..7d91871 100644
--- a/kernel/events/persistent.c
+++ b/kernel/events/persistent.c
@@ -16,6 +16,19 @@ struct pers_event_desc {
 
 static DEFINE_PER_CPU(struct list_head, pers_events);
 
+static struct pers_event_desc
+*get_persistent_event(int cpu, struct perf_event_attr *attr)
+{
+	struct pers_event_desc *desc;
+
+	list_for_each_entry(desc, &per_cpu(pers_events, cpu), plist) {
+		if (desc->event->attr.config == attr->config)
+			return desc;
+	}
+
+	return NULL;
+}
+
 static struct perf_event *
 add_persistent_event_on_cpu(unsigned int cpu, struct perf_event_attr *attr,
 			    unsigned nr_pages)
@@ -58,18 +71,13 @@ out:
 
 static void del_persistent_event(int cpu, struct perf_event_attr *attr)
 {
-	struct pers_event_desc *desc, *tmp;
-	struct perf_event *event = NULL;
-
-	list_for_each_entry_safe(desc, tmp, &per_cpu(pers_events, cpu), plist) {
-		if (desc->event->attr.config == attr->config) {
-			event = desc->event;
-			break;
-		}
-	}
+	struct pers_event_desc *desc;
+	struct perf_event *event;
 
-	if (!event)
+	desc = get_persistent_event(cpu, attr);
+	if (!desc)
 		return;
+	event = desc->event;
 
 	list_del(&desc->plist);
 
@@ -161,11 +169,11 @@ int perf_get_persistent_event_fd(unsigned cpu, struct perf_event_attr *attr)
 	if (cpu >= (unsigned)nr_cpu_ids)
 		return -EINVAL;
 
-	list_for_each_entry(desc, &per_cpu(pers_events, cpu), plist)
-		if (desc->event->attr.config == attr->config)
-			return __alloc_persistent_event_fd(desc);
+	desc = get_persistent_event(cpu, attr);
+	if (!desc)
+		return -ENODEV;
 
-	return -ENODEV;
+	return __alloc_persistent_event_fd(desc);
 }
 
 
-- 
1.8.1.1