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>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 83505a35afba10864ac8d6e0012680a72f968cb7..7ab734fbaeeb0c55d1c56c4b73f73be58799bc88 100644 (file)
--- 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);