Make sure that userspace does not retrieve stale asynchronous or

completion events after destroying a CQ, QP or SRQ.  We do this by
sweeping the event lists before returning from a destroy calls, and
then return the number of events already reported before the destroy
call.  This allows userspace wait until it has processed all events
for an object returned from the kernel before it frees its context for
the object.

The ABI of the destroy CQ, destroy QP and destroy SRQ commands has to
change to return the event count, so bump the ABI version from 1 to 2.
The userspace libibverbs library has already been updated to handle
both the old and new ABI versions.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/uverbs.h

@@ -76,20 +76,28 @@ struct ib_uverbs_file {
 	struct ib_uverbs_event_file	        comp_file[1];
 };
 
-struct ib_uverbs_async_event {
-	struct ib_uverbs_async_event_desc	desc;
+struct ib_uverbs_event {
+	union {
+		struct ib_uverbs_async_event_desc	async;
+		struct ib_uverbs_comp_event_desc	comp;
+	}					desc;
 	struct list_head			list;
+	struct list_head			obj_list;
+	u32				       *counter;
 };
 
-struct ib_uverbs_comp_event {
-	struct ib_uverbs_comp_event_desc	desc;
-	struct list_head			list;
+struct ib_uevent_object {
+	struct ib_uobject	uobject;
+	struct list_head	event_list;
+	u32			events_reported;
 };
 
-struct ib_uobject_mr {
-	struct ib_uobject			uobj;
-	struct page			       *page_list;
-	struct scatterlist		       *sg_list;
+struct ib_ucq_object {
+	struct ib_uobject	uobject;
+	struct list_head	comp_list;
+	struct list_head	async_list;
+	u32			comp_events_reported;
+	u32			async_events_reported;
 };
 
 extern struct semaphore ib_uverbs_idr_mutex;