RDMA/ucma: Fix rdma_ucm_query_ib_service_resp struct padding

On a few 32-bit architectures, the newly added ib_user_service_rec
structure is not 64-bit aligned the way it is on most regular ones.

Add explicit padding into the rdma_ucm_query_ib_service_resp and
rdma_ucm_resolve_ib_service structures that embed it, so that the layout
is compatible across all of them.

This is an ABI change on i386, aligning it with x86_64 and the other
64-bit architectures to avoid having to use a compat ioctl handler.

Fixes: 810f874 ("RDMA/ucma: Support query resolved service records")
Link: https://patch.msgid.link/r/20251208133311.313977-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Author: arndb

include/uapi/rdma/rdma_user_cm.h

@@ -192,6 +192,7 @@ struct rdma_ucm_query_path_resp {
 
 struct rdma_ucm_query_ib_service_resp {
 	__u32 num_service_recs;
+	__u32 reserved;
 	struct ib_user_service_rec recs[];
 };
 
@@ -354,14 +355,15 @@ enum {
 
 #define RDMA_USER_CM_IB_SERVICE_NAME_SIZE 64
 struct rdma_ucm_ib_service {
-	__u64 service_id;
+	__aligned_u64 service_id;
 	__u8  service_name[RDMA_USER_CM_IB_SERVICE_NAME_SIZE];
 	__u32 flags;
 	__u32 reserved;
 };
 
 struct rdma_ucm_resolve_ib_service {
 	__u32 id;
+	__u32 reserved;
 	struct rdma_ucm_ib_service ibs;
 };