[RFC PATCH 07/20] famfs: Add include/linux/famfs_ioctl.h

[John Groves <John@Groves.net>]

Add uapi include file for famfs. The famfs user space uses ioctl on
individual files to pass in mapping information and file size. This
would be hard to do via sysfs or other means, since it's
file-specific.

Signed-off-by: John Groves <john@groves.net>
---
 include/uapi/linux/famfs_ioctl.h | 56 ++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 include/uapi/linux/famfs_ioctl.h

diff --git a/include/uapi/linux/famfs_ioctl.h b/include/uapi/linux/famfs_ioctl.h
new file mode 100644
index 000000000000..6b3e6452d02f
--- /dev/null
+++ b/include/uapi/linux/famfs_ioctl.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * famfs - dax file system for shared fabric-attached memory
+ *
+ * Copyright 2023-2024 Micron Technology, Inc.
+ *
+ * This file system, originally based on ramfs the dax support from xfs,
+ * is intended to allow multiple host systems to mount a common file system
+ * view of dax files that map to shared memory.
+ */
+#ifndef FAMFS_IOCTL_H
+#define FAMFS_IOCTL_H
+
+#include <linux/ioctl.h>
+#include <linux/uuid.h>
+
+#define FAMFS_MAX_EXTENTS 2
+
+enum extent_type {
+	SIMPLE_DAX_EXTENT = 13,
+	INVALID_EXTENT_TYPE,
+};
+
+struct famfs_extent {
+	__u64              offset;
+	__u64              len;
+};
+
+enum famfs_file_type {
+	FAMFS_REG,
+	FAMFS_SUPERBLOCK,
+	FAMFS_LOG,
+};
+
+/**
+ * struct famfs_ioc_map
+ *
+ * This is the metadata that indicates where the memory is for a famfs file
+ */
+struct famfs_ioc_map {
+	enum extent_type          extent_type;
+	enum famfs_file_type      file_type;
+	__u64                     file_size;
+	__u64                     ext_list_count;
+	struct famfs_extent       ext_list[FAMFS_MAX_EXTENTS];
+};
+
+#define FAMFSIOC_MAGIC 'u'
+
+/* famfs file ioctl opcodes */
+#define FAMFSIOC_MAP_CREATE    _IOW(FAMFSIOC_MAGIC, 1, struct famfs_ioc_map)
+#define FAMFSIOC_MAP_GET       _IOR(FAMFSIOC_MAGIC, 2, struct famfs_ioc_map)
+#define FAMFSIOC_MAP_GETEXT    _IOR(FAMFSIOC_MAGIC, 3, struct famfs_extent)
+#define FAMFSIOC_NOP           _IO(FAMFSIOC_MAGIC,  4)
+
+#endif /* FAMFS_IOCTL_H */
-- 
2.43.0