ring-buffer: Remove unused function ring_buffer_nr_pages()

Because ring_buffer_nr_pages() is not an inline function and user accesses
buffer->buffers[cpu]->nr_pages directly, the function ring_buffer_nr_pages
is removed.
Signed-off-by: Jianhui Zhou <912460177@qq.com>
Link: https://lore.kernel.org/tencent_F4A7E9AB337F44E0F4B858D07D19EF460708@qq.comSigned-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

include/linux/ring_buffer.h

@@ -193,7 +193,6 @@ void ring_buffer_set_clock(struct trace_buffer *buffer,
 void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs);
 bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer);
 
-size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu);
 size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu);
 
 struct buffer_data_read_page;

kernel/trace/ring_buffer.c

@@ -692,18 +692,6 @@ u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
 	return ts;
 }
 
-/**
- * ring_buffer_nr_pages - get the number of buffer pages in the ring buffer
- * @buffer: The ring_buffer to get the number of pages from
- * @cpu: The cpu of the ring_buffer to get the number of pages from
- *
- * Returns the number of pages used by a per_cpu buffer of the ring buffer.
- */
-size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu)
-{
-	return buffer->buffers[cpu]->nr_pages;
-}
-
 /**
  * ring_buffer_nr_dirty_pages - get the number of used pages in the ring buffer
  * @buffer: The ring_buffer to get the number of pages from