ring-buffer: Have ring_buffer_iter_empty() return true when empty

[pandora-kernel.git] / kernel / trace / ring_buffer.c

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2a6f853..d6899c4 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2879,11 +2879,23 @@ EXPORT_SYMBOL_GPL(ring_buffer_iter_reset);
 int ring_buffer_iter_empty(struct ring_buffer_iter *iter)
 {
        struct ring_buffer_per_cpu *cpu_buffer;
+       struct buffer_page *reader;
+       struct buffer_page *head_page;
+       struct buffer_page *commit_page;
+       unsigned commit;
 
        cpu_buffer = iter->cpu_buffer;
 
-       return iter->head_page == cpu_buffer->commit_page &&
-               iter->head == rb_commit_index(cpu_buffer);
+       /* Remember, trace recording is off when iterator is in use */
+       reader = cpu_buffer->reader_page;
+       head_page = cpu_buffer->head_page;
+       commit_page = cpu_buffer->commit_page;
+       commit = rb_page_commit(commit_page);
+
+       return ((iter->head_page == commit_page && iter->head == commit) ||
+               (iter->head_page == reader && commit_page == head_page &&
+                head_page->read == commit &&
+                iter->head == rb_page_commit(cpu_buffer->reader_page)));
 }
 EXPORT_SYMBOL_GPL(ring_buffer_iter_empty);