Extract the group moving code in function sys_perf_event_open() to create
a new function perf_event_move_group().
The subsequent change would add a new function
perf_event_create_group_kernel_counters() which is used to create group
events in kernel space. The function also needs to do same group moving
for group leader event just like function sys_perf_event_open() does. So
extract the moving code into a separate function to avoid the code
duplication.
Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
---
kernel/events/core.c | 82 ++++++++++++++++++++++++--------------------
1 file changed, 45 insertions(+), 37 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d485dac2b55f..953e3d3a1664 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -12388,6 +12388,48 @@ static int perf_event_group_leader_check(struct perf_event *group_leader,
return 0;
}
+static void perf_event_move_group(struct perf_event *group_leader,
+ struct perf_event_pmu_context *pmu_ctx,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *sibling;
+
+ perf_remove_from_context(group_leader, 0);
+ put_pmu_ctx(group_leader->pmu_ctx);
+
+ for_each_sibling_event(sibling, group_leader) {
+ perf_remove_from_context(sibling, 0);
+ put_pmu_ctx(sibling->pmu_ctx);
+ }
+
+ /*
+ * Install the group siblings before the group leader.
+ *
+ * Because a group leader will try and install the entire group
+ * (through the sibling list, which is still in-tact), we can
+ * end up with siblings installed in the wrong context.
+ *
+ * By installing siblings first we NO-OP because they're not
+ * reachable through the group lists.
+ */
+ for_each_sibling_event(sibling, group_leader) {
+ sibling->pmu_ctx = pmu_ctx;
+ get_pmu_ctx(pmu_ctx);
+ perf_event__state_init(sibling);
+ perf_install_in_context(ctx, sibling, sibling->cpu);
+ }
+
+ /*
+ * Removing from the context ends up with disabled
+ * event. What we want here is event in the initial
+ * startup state, ready to be add into new context.
+ */
+ group_leader->pmu_ctx = pmu_ctx;
+ get_pmu_ctx(pmu_ctx);
+ perf_event__state_init(group_leader);
+ perf_install_in_context(ctx, group_leader, group_leader->cpu);
+}
+
/**
* sys_perf_event_open - open a performance event, associate it to a task/cpu
*
@@ -12403,7 +12445,7 @@ SYSCALL_DEFINE5(perf_event_open,
{
struct perf_event *group_leader = NULL, *output_event = NULL;
struct perf_event_pmu_context *pmu_ctx;
- struct perf_event *event, *sibling;
+ struct perf_event *event;
struct perf_event_attr attr;
struct perf_event_context *ctx;
struct file *event_file = NULL;
@@ -12635,42 +12677,8 @@ SYSCALL_DEFINE5(perf_event_open,
* where we start modifying current state.
*/
- if (move_group) {
- perf_remove_from_context(group_leader, 0);
- put_pmu_ctx(group_leader->pmu_ctx);
-
- for_each_sibling_event(sibling, group_leader) {
- perf_remove_from_context(sibling, 0);
- put_pmu_ctx(sibling->pmu_ctx);
- }
-
- /*
- * Install the group siblings before the group leader.
- *
- * Because a group leader will try and install the entire group
- * (through the sibling list, which is still in-tact), we can
- * end up with siblings installed in the wrong context.
- *
- * By installing siblings first we NO-OP because they're not
- * reachable through the group lists.
- */
- for_each_sibling_event(sibling, group_leader) {
- sibling->pmu_ctx = pmu_ctx;
- get_pmu_ctx(pmu_ctx);
- perf_event__state_init(sibling);
- perf_install_in_context(ctx, sibling, sibling->cpu);
- }
-
- /*
- * Removing from the context ends up with disabled
- * event. What we want here is event in the initial
- * startup state, ready to be add into new context.
- */
- group_leader->pmu_ctx = pmu_ctx;
- get_pmu_ctx(pmu_ctx);
- perf_event__state_init(group_leader);
- perf_install_in_context(ctx, group_leader, group_leader->cpu);
- }
+ if (move_group)
+ perf_event_move_group(group_leader, pmu_ctx, ctx);
/*
* Precalculate sample_data sizes; do while holding ctx::mutex such
--
2.34.1
