Major cleanup, moving things around, documenting, etc

index 1dbed4e..99f79db 100644
@@ -26,8 +26,10 @@
  */
 #define RCHAN_GLOBAL_BUFFER		0x00000001	/* not using per-cpu */
 
-struct relay_page
-{
+/*
+ * For page lists
+ */
+struct relay_page {
 	struct page *page;
 	struct list_head list;
 	struct relay_page_callbacks *cb;

@@ -37,17 +39,16 @@ struct relay_page
 /*
  * Per-cpu relay channel buffer
  */
-struct rchan_buf
-{
+struct rchan_buf {
 	struct rchan *chan;		/* associated channel */
 	wait_queue_head_t read_wait;	/* reader wait queue */
 	struct timer_list timer; 	/* reader wake-up timer */
 	struct dentry *dentry;		/* channel file dentry */
 	struct kref kref;		/* channel buffer refcount */
 	struct list_head pages;		/* current set of unconsumed pages */
+	size_t nr_pages;		/* number of unconsumed pages */
 	spinlock_t lock;		/* protect pages list */
 	size_t consumed_offset;		/* bytes consumed in cur page */
-	size_t nr_pages;		/* number of unconsumed pages */
 	unsigned int finalized;		/* buffer has been finalized */
 	unsigned int cpu;		/* this buf's cpu */
 } ____cacheline_aligned;

@@ -115,40 +116,25 @@ struct rchan_callbacks
 struct relay_page_callbacks
 {
 	/*
-	 * page_released - called on switch to a new page
-	 * @buf: the channel buffer containing the new page
-	 * @page_data: the start of the new page
+	 * page_released - notification that a page is ready for re-use
+	 * @page: the released page
+	 * @private_data: user-defined data associated with the page
 	 *
-	 * This is simply a notification that a new page has been
-	 * switched to.  The default version does nothing but call
-	 * relay_wakeup_readers().  Clients who override this callback
-	 * should also call relay_wakeup_readers() to get that default
-	 * behavior in addition to whatever they add.  Clients who
-	 * don't want to wake up readers should just not call it.
-	 * Clients can use the channel private_data to track previous
-	 * pages, determine whether this is the first page, etc.
-	 *
-	 * NOTE: the client can reserve bytes at the beginning of the new
-	 *       page by calling page_start_reserve() in this callback.
+	 * This callback is a notification that a given page has been
+	 * read by userspace and can be re-used.  Always called in
+	 * user context.
 	 */
 	void (*page_released) (struct page *page, void *private_data);
 
 	/*
-	 * page_stolen - called on switch to a new page
-	 * @buf: the channel buffer containing the new page
-	 * @page_data: the start of the new page
-	 *
-	 * This is simply a notification that a new page has been
-	 * switched to.  The default version does nothing but call
-	 * relay_wakeup_readers().  Clients who override this callback
-	 * should also call relay_wakeup_readers() to get that default
-	 * behavior in addition to whatever they add.  Clients who
-	 * don't want to wake up readers should just not call it.
-	 * Clients can use the channel private_data to track previous
-	 * pages, determine whether this is the first page, etc.
+	 * page_released - notification that a page has been stolen
+	 * @page: the stolen page
+	 * @private_data: user-defined data associated with the page
 	 *
-	 * NOTE: the client can reserve bytes at the beginning of the new
-	 *       page by calling page_start_reserve() in this callback.
+	 * This callback is a notification that a given page has been
+	 * stolen by userspace.  The owner may wish to replace it;
+	 * this gives it the opportunity to do so.  Always called in
+	 * user context.
 	 */
 	void (*page_stolen) (struct page *page, void *private_data);
 };

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