Merge remote-tracking branch 'origin' into irqdomain/next

1 files changed, 7 insertions, 3 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 1d0f6a8a0e5e..49491fa7daa2 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1075,6 +1075,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int nr_pages, int cpu)
         rb_init_page(bpage->page);
 
         INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+        INIT_LIST_HEAD(&cpu_buffer->new_pages);
 
         ret = rb_allocate_pages(cpu_buffer, nr_pages);
         if (ret < 0)
@@ -1346,10 +1347,9 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned int nr_pages)
                          * If something was added to this page, it was full
                          * since it is not the tail page. So we deduct the
                          * bytes consumed in ring buffer from here.
-                         * No need to update overruns, since this page is
-                         * deleted from ring buffer and its entries are
-                         * already accounted for.
+                         * Increment overrun to account for the lost events.
                          */
+                        local_add(page_entries, &cpu_buffer->overrun);
                         local_sub(BUF_PAGE_SIZE, &cpu_buffer->entries_bytes);
                 }
 
@@ -3239,6 +3239,10 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
         if (cpu_buffer->commit_page == cpu_buffer->reader_page)
                 goto out;
 
+        /* Don't bother swapping if the ring buffer is empty */
+        if (rb_num_of_entries(cpu_buffer) == 0)
+                goto out;
+
         /*
          * Reset the reader page to size zero.
          */