Subject: Re: [BUG -next] ./usr/include/cxl/features.h:11:10: fatal error: uuid/uuid.h: No such file or directory

From: Jason Gunthorpe <[email-masked]>
Date: Mon, 31 Mar 2025 10:24:39 -0300

On Fri, Mar 28, 2025 at 05:26:42PM -0700, Dave Jiang wrote:
> > For now the following builds for me, but it is a quite a mess to undo
> > the assumption that that the hardware object definitions can not use
> > uuid_t:
> 
> +Jason.

Seems invasive?

Maybe just like below?

Dave please send a patch for whatever is good..

diff --git a/include/uapi/cxl/features.h b/include/uapi/cxl/features.h
index d6db8984889fa6..e31862dfc2eda0 100644
--- a/include/uapi/cxl/features.h
+++ b/include/uapi/cxl/features.h
@@ -8,10 +8,16 @@
 #define _UAPI_CXL_FEATURES_H_
 
 #include <linux/types.h>
-#ifndef __KERNEL__
-#include <uuid/uuid.h>
-#else
+
+typedef struct {
+	__u8 b[16];
+} __kernel_uuid_t;
+
+#ifdef __KERNEL__
 #include <linux/uuid.h>
+static_assert(sizeof(__kernel_uuid_t) == sizeof(uuid_t) &&
+	      __alignof__(__kernel_uuid_t) == __alignof__(uuid_t));
+#define __kernel_uuid_t uuid_t
 #endif
 
 /*
@@ -60,7 +66,7 @@ struct cxl_mbox_get_sup_feats_in {
  * Get Supported Features Supported Feature Entry
  */
 struct cxl_feat_entry {
-	uuid_t uuid;
+	__kernel_uuid_t uuid;
 	__le16 id;
 	__le16 get_feat_size;
 	__le16 set_feat_size;
@@ -110,7 +116,7 @@ struct cxl_mbox_get_sup_feats_out {
  * CXL spec r3.2 section 8.2.9.6.2 Table 8-99
  */
 struct cxl_mbox_get_feat_in {
-	uuid_t uuid;
+	__kernel_uuid_t uuid;
 	__le16 offset;
 	__le16 count;
 	__u8 selection;
@@ -143,7 +149,7 @@ enum cxl_get_feat_selection {
  */
 struct cxl_mbox_set_feat_in {
 	__struct_group(cxl_mbox_set_feat_hdr, hdr, /* no attrs */,
-		uuid_t uuid;
+		__kernel_uuid_t uuid;
 		__le32 flags;
 		__le16 offset;
 		__u8 version;