/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */#ifndef _LINUX_CACHEFILES_H#define _LINUX_CACHEFILES_H #include <linux/types.h>#include <linux/ioctl.h> /* * Fscache ensures that the maximum length of cookie key is 255. The volume key * is controlled by netfs, and generally no bigger than 255. */#define CACHEFILES_MSG_MAX_SIZE	1024 enum cachefiles_opcode {	CACHEFILES_OP_OPEN,	CACHEFILES_OP_CLOSE,	CACHEFILES_OP_READ,}; /* * Message Header * * @msg_id	a unique ID identifying this message * @opcode	message type, CACHEFILE_OP_* * @len		message length, including message header and following data * @object_id	a unique ID identifying a cache file * @data	message type specific payload */struct cachefiles_msg {	__u32 msg_id;	__u32 opcode;	__u32 len;	__u32 object_id;	__u8  data[];}; /* * @data contains the volume_key followed directly by the cookie_key. volume_key * is a NUL-terminated string; @volume_key_size indicates the size of the volume * key in bytes. cookie_key is binary data, which is netfs specific; * @cookie_key_size indicates the size of the cookie key in bytes. * * @fd identifies an anon_fd referring to the cache file. */struct cachefiles_open {	__u32 volume_key_size;	__u32 cookie_key_size;	__u32 fd;	__u32 flags;	__u8  data[];}; /* * @off		indicates the starting offset of the requested file range * @len		indicates the length of the requested file range */struct cachefiles_read {	__u64 off;	__u64 len;}; /* * Reply for READ request * @arg for this ioctl is the @id field of READ request. */#define CACHEFILES_IOC_READ_COMPLETE	_IOW(0x98, 1, int) #endif