ring-buffer: pass in lockdep class key for reader_lock

[safe/jmp/linux-2.6] / include / linux / ring_buffer.h

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index f134582..8670f15 100644 (file)
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -105,7 +105,19 @@ void ring_buffer_discard_commit(struct ring_buffer *buffer,
  * size is in bytes for each per CPU buffer.
  */
 struct ring_buffer *
-ring_buffer_alloc(unsigned long size, unsigned flags);
+__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
+
+/*
+ * Because the ring buffer is generic, if other users of the ring buffer get
+ * traced by ftrace, it can produce lockdep warnings. We need to keep each
+ * ring buffer's lock class separate.
+ */
+#define ring_buffer_alloc(size, flags)                 \
+({                                                     \
+       static struct lock_class_key __key;             \
+       __ring_buffer_alloc((size), (flags), &__key);   \
+})
+
 void ring_buffer_free(struct ring_buffer *buffer);
 
 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);