[PATCH v8 08/14] perf/core: set the event->owner before event_init

[Wei Wang]

Kernel and user events can be distinguished by checking event->owner. Some
pmu driver implementation may need to know event->owner in event_init. For
example, intel_pmu_setup_lbr_filter treats a kernel event with
exclude_host set as an lbr event created for guest lbr emulation, which
doesn't need a pmu counter.

So move the event->owner assignment into perf_event_alloc to have it
set before event_init is called.

Signed-off-by: Wei Wang <wei.w.w...@intel.com>
---
 kernel/events/core.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0463c11..7663f85 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10288,6 +10288,7 @@ static void account_event(struct perf_event *event)
 static struct perf_event *
 perf_event_alloc(struct perf_event_attr *attr, int cpu,
                 struct task_struct *task,
+                struct task_struct *owner,
                 struct perf_event *group_leader,
                 struct perf_event *parent_event,
                 perf_overflow_handler_t overflow_handler,
@@ -10340,6 +10341,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
        event->group_leader     = group_leader;
        event->pmu              = NULL;
        event->oncpu            = -1;
+       event->owner            = owner;
 
        event->parent           = parent_event;
 
@@ -10891,7 +10893,7 @@ SYSCALL_DEFINE5(perf_event_open,
        if (flags & PERF_FLAG_PID_CGROUP)
                cgroup_fd = pid;
 
-       event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
+       event = perf_event_alloc(&attr, cpu, task, current, group_leader, NULL,
                                 NULL, NULL, cgroup_fd);
        if (IS_ERR(event)) {
                err = PTR_ERR(event);
@@ -11153,8 +11155,6 @@ SYSCALL_DEFINE5(perf_event_open,
        perf_event__header_size(event);
        perf_event__id_header_size(event);
 
-       event->owner = current;
-
        perf_install_in_context(ctx, event, event->cpu);
        perf_unpin_context(ctx);
 
@@ -11231,16 +11231,13 @@ perf_event_create_kernel_counter(struct 
perf_event_attr *attr, int cpu,
         * Get the target context (task or percpu):
         */
 
-       event = perf_event_alloc(attr, cpu, task, NULL, NULL,
+       event = perf_event_alloc(attr, cpu, task, TASK_TOMBSTONE, NULL, NULL,
                                 overflow_handler, context, -1);
        if (IS_ERR(event)) {
                err = PTR_ERR(event);
                goto err;
        }
 
-       /* Mark owner so we could distinguish it from user events. */
-       event->owner = TASK_TOMBSTONE;
-
        ctx = find_get_context(event->pmu, task, event);
        if (IS_ERR(ctx)) {
                err = PTR_ERR(ctx);
@@ -11677,6 +11674,7 @@ inherit_event(struct perf_event *parent_event,
 
        child_event = perf_event_alloc(&parent_event->attr,
                                           parent_event->cpu,
+                                          parent_event->owner,
                                           child,
                                           group_leader, parent_event,
                                           NULL, NULL, -1);
-- 
2.7.4