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construct/include/ircd/fs/iou.h

104 lines
2.6 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_FS_IOU_H
// Public and unconditional interface for io_uring. This file is part of the
// standard include stack and available whether or not this platform is Linux
// with io_uring (>= 5.1), and whether or not it's enabled, etc. If it is not
// most of this stuff does nothing and will have null values.
extern "C"
{
struct io_uring_sqe;
}
/// Input/Output Userspace Ring buffering.
///
/// Note that fs::aio and fs::iou are never used simultaneously. If io_uring
/// is supported by both the compilation and the kernel at runtime then it
/// will be selected over AIO.
namespace ircd::fs::iou
{
struct init;
struct stats;
struct system;
struct request;
enum state :uint8_t;
// a priori
extern const bool support;
extern const size_t MAX_EVENTS;
// configuration
extern conf::item<bool> enable;
extern conf::item<size_t> max_events;
extern conf::item<size_t> max_submit;
// runtime state
extern struct stats stats;
extern struct system *system;
// util
string_view reflect(const state &);
const_iovec_view iovec(const request &);
const struct ::io_uring_sqe &sqe(const request &);
struct ::io_uring_sqe &sqe(request &);
// iterate requests
static bool for_each(const state &, const std::function<bool (const request &)> &);
static bool for_each(const std::function<bool (const request &)> &);
// count requests
static size_t count(const state &, const op &);
static size_t count(const state &);
static size_t count(const op &);
}
struct ircd::fs::iou::request
{
const fs::opts *opts {nullptr};
fs::op op {fs::op::NOOP};
std::error_code ec;
int32_t res {-1};
int32_t id {-1};
request() = default;
request(const fd &, const const_iovec_view &, const fs::opts *const &);
~request() noexcept;
};
/// Enumeration of states for a request.
enum ircd::fs::iou::state
:uint8_t
{
INVALID,
QUEUED,
SUBMITTED,
COMPLETED,
_NUM
};
/// Reuse the same stats structure as fs::aio in fs::iou
struct ircd::fs::iou::stats
:aio::stats
{
using aio::stats::stats;
};
/// Internal use; this is simply declared here for when internal headers are
/// not available for this build so a weak no-op definition can be defined.
struct ircd::fs::iou::init
{
init();
~init() noexcept;
};