RDMA/rxe: Fix uABI structure layouts for 32/64 compat

With 32 bit compilation several of the fields become misaligned here.
Fixing this is an ABI break for 32 bit rxe and it is in well used
portions of the rxe ABI.

To handle this we bump the ABI version, as expected. However the user
space driver doesn't handle it properly today, so all existing user
space continues to work.

Updated userspace will start to require the necessary kernel version.

We don't expect there to be any 32 bit users of rxe. Most likely cases,
such as ARM 32 already generally don't work because rxe does not handle
the CPU cache properly on its shared with userspace pages.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/rxe/rxe.h

@@ -59,7 +59,11 @@
 #include "rxe_verbs.h"
 #include "rxe_loc.h"
 
-#define RXE_UVERBS_ABI_VERSION		(1)
+/*
+ * Version 1 and Version 2 are identical on 64 bit machines, but on 32 bit
+ * machines Version 2 has a different struct layout.
+ */
+#define RXE_UVERBS_ABI_VERSION		2
 
 #define IB_PHYS_STATE_LINK_UP		(5)
 #define IB_PHYS_STATE_LINK_DOWN		(3)

include/uapi/rdma/rdma_user_rxe.h

@@ -58,6 +58,8 @@ struct rxe_global_route {
 struct rxe_av {
 	__u8			port_num;
 	__u8			network_type;
+	__u16			reserved1;
+	__u32			reserved2;
 	struct rxe_global_route	grh;
 	union {
 		struct sockaddr_in	_sockaddr_in;
@@ -92,10 +94,14 @@ struct rxe_send_wr {
 			__u32	remote_qkey;
 			__u16	pkey_index;
 		} ud;
+		/* reg is only used by the kernel and is not part of the uapi */
 		struct {
-			struct ib_mr *mr;
+			union {
+				struct ib_mr *mr;
+				__u64 reserved;
+			};
 			__u32        key;
-			int          access;
+			__u32        access;
 		} reg;
 	} wr;
 };
@@ -118,6 +124,7 @@ struct rxe_dma_info {
 	__u32			cur_sge;
 	__u32			num_sge;
 	__u32			sge_offset;
+	__u32			reserved;
 	union {
 		__u8		inline_data[0];
 		struct rxe_sge	sge[0];
@@ -162,6 +169,7 @@ struct rxe_create_qp_resp {
 struct rxe_create_srq_resp {
 	struct mminfo mi;
 	__u32 srq_num;
+	__u32 reserved;
 };
 
 struct rxe_modify_srq_cmd {