include/uapi/linux/dm-user.h

/* SPDX-License-Identifier: LGPL-2.0+ WITH Linux-syscall-note */
/*
 * Copyright (C) 2020 Google, Inc
 * Copyright (C) 2020 Palmer Dabbelt <palmerdabbelt@google.com>
 */

#ifndef _LINUX_DM_USER_H
#define _LINUX_DM_USER_H

#include <linux/types.h>

/*
 * dm-user proxies device mapper ops between the kernel and userspace.  It's
 * essentially just an RPC mechanism: all kernel calls create a request,
 * userspace handles that with a response.  Userspace obtains requests via
 * read() and provides responses via write().
 *
 * See Documentation/block/dm-user.rst for more information.
 */

#define DM_USER_REQ_MAP_READ 0
#define DM_USER_REQ_MAP_WRITE 1
#define DM_USER_REQ_MAP_FLUSH 2
#define DM_USER_REQ_MAP_DISCARD 3
#define DM_USER_REQ_MAP_SECURE_ERASE 4
#define DM_USER_REQ_MAP_WRITE_SAME 5
#define DM_USER_REQ_MAP_WRITE_ZEROES 6
#define DM_USER_REQ_MAP_ZONE_OPEN 7
#define DM_USER_REQ_MAP_ZONE_CLOSE 8
#define DM_USER_REQ_MAP_ZONE_FINISH 9
#define DM_USER_REQ_MAP_ZONE_APPEND 10
#define DM_USER_REQ_MAP_ZONE_RESET 11
#define DM_USER_REQ_MAP_ZONE_RESET_ALL 12

#define DM_USER_REQ_MAP_FLAG_FAILFAST_DEV 0x00001
#define DM_USER_REQ_MAP_FLAG_FAILFAST_TRANSPORT 0x00002
#define DM_USER_REQ_MAP_FLAG_FAILFAST_DRIVER 0x00004
#define DM_USER_REQ_MAP_FLAG_SYNC 0x00008
#define DM_USER_REQ_MAP_FLAG_META 0x00010
#define DM_USER_REQ_MAP_FLAG_PRIO 0x00020
#define DM_USER_REQ_MAP_FLAG_NOMERGE 0x00040
#define DM_USER_REQ_MAP_FLAG_IDLE 0x00080
#define DM_USER_REQ_MAP_FLAG_INTEGRITY 0x00100
#define DM_USER_REQ_MAP_FLAG_FUA 0x00200
#define DM_USER_REQ_MAP_FLAG_PREFLUSH 0x00400
#define DM_USER_REQ_MAP_FLAG_RAHEAD 0x00800
#define DM_USER_REQ_MAP_FLAG_BACKGROUND 0x01000
#define DM_USER_REQ_MAP_FLAG_NOWAIT 0x02000
#define DM_USER_REQ_MAP_FLAG_CGROUP_PUNT 0x04000
#define DM_USER_REQ_MAP_FLAG_NOUNMAP 0x08000
#define DM_USER_REQ_MAP_FLAG_HIPRI 0x10000
#define DM_USER_REQ_MAP_FLAG_DRV 0x20000
#define DM_USER_REQ_MAP_FLAG_SWAP 0x40000

#define DM_USER_RESP_SUCCESS 0
#define DM_USER_RESP_ERROR 1
#define DM_USER_RESP_UNSUPPORTED 2

struct dm_user_message {
	__u64 seq;
	__u64 type;
	__u64 flags;
	__u64 sector;
	__u64 len;
	__u8 buf[];
};

#endif