[PATCH] cxl/uapi: Add warning on CXL command enum

From: ira . weiny
Date: Wed Dec 07 2022 - 19:02:12 EST


From: Ira Weiny <ira.weiny@xxxxxxxxx>

The CXL command enum is exported to user space and must maintain
backwards compatibility.

Add comment that new defines must be added to the end of the list.

Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
include/uapi/linux/cxl_mem.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index c71021a2a9ed..459a3f7f764b 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -19,6 +19,10 @@
#define CXL_MEM_QUERY_COMMANDS _IOR(0xCE, 1, struct cxl_mem_query_commands)
#define CXL_MEM_SEND_COMMAND _IOWR(0xCE, 2, struct cxl_send_command)

+/*
+ * NOTE: New defines must be added to the end of the list to preserve
+ * compatibility because this enum is exported to user space.
+ */
#define CXL_CMDS \
___C(INVALID, "Invalid Command"), \
___C(IDENTIFY, "Identify Command"), \

base-commit: acb704099642bc822ef2aed223a0b8db1f7ea76e
--
2.37.2