ring-buffer: only enable ring_buffer_swap_cpu when needed

[linux-block.git] / kernel / trace / ring_buffer.c

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 1766c0e8db5a81b777e06eabb20487b68630d6b8..454e74e718cfb77b4b2b0824acc93b0ce3f90aa8 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2084,6 +2084,7 @@ rb_reserve_next_event(struct ring_buffer *buffer,
 
        rb_start_commit(cpu_buffer);
 
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
        /*
         * Due to the ability to swap a cpu buffer from a buffer
         * it is possible it was swapped before we committed.
@@ -2096,6 +2097,7 @@ rb_reserve_next_event(struct ring_buffer *buffer,
                local_dec(&cpu_buffer->commits);
                return NULL;
        }
+#endif
 
        length = rb_calculate_event_length(length);
  again:
@@ -3498,6 +3500,7 @@ int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu)
 }
 EXPORT_SYMBOL_GPL(ring_buffer_empty_cpu);
 
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
 /**
  * ring_buffer_swap_cpu - swap a CPU buffer between two ring buffers
  * @buffer_a: One buffer to swap with
@@ -3573,6 +3576,7 @@ out:
        return ret;
 }
 EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
+#endif /* CONFIG_RING_BUFFER_ALLOW_SWAP */
 
 /**
  * ring_buffer_alloc_read_page - allocate a page to read from buffer