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>

1 files changed, 20 insertions, 1 deletions

diff --git a/include/rdma/ib_user_verbs.h b/include/rdma/ib_user_verbs.h
index 7ebb01c8f996..fd85725391a4 100644
--- a/include/rdma/ib_user_verbs.h
+++ b/include/rdma/ib_user_verbs.h
@@ -42,7 +42,7 @@
  * Increment this value if any changes that break userspace ABI
  * compatibility are made.
  */
-#define IB_USER_VERBS_ABI_VERSION       1
+#define IB_USER_VERBS_ABI_VERSION       2
 
 enum {
         IB_USER_VERBS_CMD_QUERY_PARAMS,
@@ -292,7 +292,14 @@ struct ib_uverbs_create_cq_resp {
 };
 
 struct ib_uverbs_destroy_cq {
+        __u64 response;
         __u32 cq_handle;
+        __u32 reserved;
+};
+
+struct ib_uverbs_destroy_cq_resp {
+        __u32 comp_events_reported;
+        __u32 async_events_reported;
 };
 
 struct ib_uverbs_create_qp {
@@ -372,7 +379,13 @@ struct ib_uverbs_modify_qp_resp {
 };
 
 struct ib_uverbs_destroy_qp {
+        __u64 response;
         __u32 qp_handle;
+        __u32 reserved;
+};
+
+struct ib_uverbs_destroy_qp_resp {
+        __u32 events_reported;
 };
 
 struct ib_uverbs_attach_mcast {
@@ -416,7 +429,13 @@ struct ib_uverbs_modify_srq {
 };
 
 struct ib_uverbs_destroy_srq {
+        __u64 response;
         __u32 srq_handle;
+        __u32 reserved;
+};
+
+struct ib_uverbs_destroy_srq_resp {
+        __u32 events_reported;
 };
 
 #endif /* IB_USER_VERBS_H */