perf: Simplify perf_event_exit_task_context()

Instead of jumping through hoops to make sure to find (and exit) each
event, do it the simple straight fwd way.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-tij931199thfkys8vbnokdpf@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 1 insertions, 16 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 83505a35afba..7ab734fbaeeb 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7485,24 +7485,9 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
          */
         mutex_lock(&child_ctx->mutex);
 
-again:
-        list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
-                                 group_entry)
-                __perf_event_exit_task(child_event, child_ctx, child);
-
-        list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
-                                 group_entry)
+        list_for_each_entry_rcu(child_event, &child_ctx->event_list, event_entry)
                 __perf_event_exit_task(child_event, child_ctx, child);
 
-        /*
-         * If the last event was a group event, it will have appended all
-         * its siblings to the list, but we obtained 'tmp' before that which
-         * will still point to the list head terminating the iteration.
-         */
-        if (!list_empty(&child_ctx->pinned_groups) ||
-            !list_empty(&child_ctx->flexible_groups))
-                goto again;
-
         mutex_unlock(&child_ctx->mutex);
 
         put_ctx(child_ctx);