ring-buffer: Remove unused function ring_buffer_page_len()

Commit 6b7e633 ("tracing: Remove extra zeroing out of the ring
buffer page") removed the only caller of ring_buffer_page_len(). The
function is now unused and may be removed.

Link: http://lkml.kernel.org/r/20181228133847.106177-1-mbenes@suse.cz

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

include/linux/ring_buffer.h

@@ -187,8 +187,6 @@ void ring_buffer_set_clock(struct ring_buffer *buffer,
 void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs);
 bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer);
 
-size_t ring_buffer_page_len(void *page);
-
 size_t ring_buffer_nr_pages(struct ring_buffer *buffer, int cpu);
 size_t ring_buffer_nr_dirty_pages(struct ring_buffer *buffer, int cpu);
 

kernel/trace/ring_buffer.c

@@ -353,20 +353,6 @@ static void rb_init_page(struct buffer_data_page *bpage)
 	local_set(&bpage->commit, 0);
 }
 
-/**
- * ring_buffer_page_len - the size of data on the page.
- * @page: The page to read
- *
- * Returns the amount of data on the page, including buffer page header.
- */
-size_t ring_buffer_page_len(void *page)
-{
-	struct buffer_data_page *bpage = page;
-
-	return (local_read(&bpage->commit) & ~RB_MISSED_FLAGS)
-		+ BUF_PAGE_HDR_SIZE;
-}
-
 /*
  * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
  * this issue out.