[PATCH 06/24] gtrace: Replace owner PID with perf_event pointer in gtrace_path

[Zane Leung]

Replace 'pid_t owner' with 'struct perf_event *event' in struct gtrace_path.
This allows component drivers to directly access the perf_event for PMU
configuration.

Signed-off-by: Zane Leung <liangzhen@xxxxxxxxxxxxxxxxxx>
---
 drivers/hwtracing/gtrace/gtrace-core.c | 12 ++++++++++--
 drivers/hwtracing/gtrace/gtrace-perf.c |  2 +-
 include/linux/gtrace.h                 |  2 +-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/hwtracing/gtrace/gtrace-core.c b/drivers/hwtracing/gtrace/gtrace-core.c
index cae0a7fa820f..3f55d8b7302d 100644
--- a/drivers/hwtracing/gtrace/gtrace-core.c
+++ b/drivers/hwtracing/gtrace/gtrace-core.c
@@ -13,6 +13,7 @@
 #include <linux/spinlock.h>
 #include <linux/xarray.h>
 #include <linux/gtrace.h>
+#include <linux/perf_event.h>
 
 #define GTRACE_POLL_TIMEOUT_US_DEFAULT	10
 
@@ -665,10 +666,16 @@ static int __gtrace_comp_start(struct gtrace_component *comp,
 
 	raw_spin_lock_irqsave(&cpriv->lock, flags);
 	if (cpriv->start_count) {
-		if (cpriv->owner != path->owner || cpriv->mode != path->mode) {
+		if (cpriv->mode != path->mode) {
 			ret = -EBUSY;
 			goto out;
 		}
+		if (cpriv->mode == GTRACE_COMPONENT_MODE_PERF) {
+			if (cpriv->owner != task_pid_nr(path->event->owner)) {
+				ret = -EBUSY;
+				goto out;
+			}
+		}
 	} else {
 		if (gtdrv->start) {
 			comp->path = path;
@@ -678,8 +685,9 @@ static int __gtrace_comp_start(struct gtrace_component *comp,
 				goto out;
 			}
 		}
-		cpriv->owner = path->owner;
 		cpriv->mode = path->mode;
+		if (cpriv->mode == GTRACE_COMPONENT_MODE_PERF)
+			cpriv->owner = task_pid_nr(path->event->owner);
 	}
 
 	cpriv->start_count++;
diff --git a/drivers/hwtracing/gtrace/gtrace-perf.c b/drivers/hwtracing/gtrace/gtrace-perf.c
index 703c12b95665..2fcfbae9acf6 100644
--- a/drivers/hwtracing/gtrace/gtrace-perf.c
+++ b/drivers/hwtracing/gtrace/gtrace-perf.c
@@ -137,7 +137,7 @@ static void *gtrace_setup_aux(struct perf_event *event, void **pages,
 			continue;
 		}
 
-		path->owner = task_pid_nr(event->owner);
+		path->event = event;
 		*gtrace_event_cpu_path_ptr(event_data, cpu) = path;
 	}
 
diff --git a/include/linux/gtrace.h b/include/linux/gtrace.h
index 76b1aa9cfe79..3d769b405030 100644
--- a/include/linux/gtrace.h
+++ b/include/linux/gtrace.h
@@ -325,7 +325,7 @@ struct gtrace_path {
 	enum gtrace_component_mode	mode;
 	u32				trace_id;
 #define GTRACE_INVALID_TRACE_ID	0
-	pid_t				owner;
+	struct perf_event		*event;
 };
 
 struct gtrace_component *gtrace_path_source(struct gtrace_path *path);
-- 
2.34.1