53e1b68390
This follows what the kernel is doing, c.f. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5fd54ace4721fc5ce2bb5aef6318fcf17f421460.
94 lines
2.6 KiB
C
94 lines
2.6 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
|
|
#pragma once
|
|
|
|
/***
|
|
This file is part of systemd.
|
|
|
|
Copyright 2014 David Herrmann <dh.herrmann@gmail.com>
|
|
|
|
systemd is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
systemd is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
***/
|
|
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
#include <sys/types.h>
|
|
|
|
#include "macro.h"
|
|
|
|
/* See source file for an API description. */
|
|
|
|
typedef struct Barrier Barrier;
|
|
|
|
enum {
|
|
BARRIER_SINGLE = 1LL,
|
|
BARRIER_ABORTION = INT64_MAX,
|
|
|
|
/* bias values to store state; keep @WE < @THEY < @I */
|
|
BARRIER_BIAS = INT64_MIN,
|
|
BARRIER_WE_ABORTED = BARRIER_BIAS + 1LL,
|
|
BARRIER_THEY_ABORTED = BARRIER_BIAS + 2LL,
|
|
BARRIER_I_ABORTED = BARRIER_BIAS + 3LL,
|
|
};
|
|
|
|
enum {
|
|
BARRIER_PARENT,
|
|
BARRIER_CHILD,
|
|
};
|
|
|
|
struct Barrier {
|
|
int me;
|
|
int them;
|
|
int pipe[2];
|
|
int64_t barriers;
|
|
};
|
|
|
|
#define BARRIER_NULL {-1, -1, {-1, -1}, 0}
|
|
|
|
int barrier_create(Barrier *obj);
|
|
void barrier_destroy(Barrier *b);
|
|
|
|
DEFINE_TRIVIAL_CLEANUP_FUNC(Barrier*, barrier_destroy);
|
|
|
|
void barrier_set_role(Barrier *b, unsigned int role);
|
|
|
|
bool barrier_place(Barrier *b);
|
|
bool barrier_abort(Barrier *b);
|
|
|
|
bool barrier_wait_next(Barrier *b);
|
|
bool barrier_wait_abortion(Barrier *b);
|
|
bool barrier_sync_next(Barrier *b);
|
|
bool barrier_sync(Barrier *b);
|
|
|
|
static inline bool barrier_i_aborted(Barrier *b) {
|
|
return IN_SET(b->barriers, BARRIER_I_ABORTED, BARRIER_WE_ABORTED);
|
|
}
|
|
|
|
static inline bool barrier_they_aborted(Barrier *b) {
|
|
return IN_SET(b->barriers, BARRIER_THEY_ABORTED, BARRIER_WE_ABORTED);
|
|
}
|
|
|
|
static inline bool barrier_we_aborted(Barrier *b) {
|
|
return b->barriers == BARRIER_WE_ABORTED;
|
|
}
|
|
|
|
static inline bool barrier_is_aborted(Barrier *b) {
|
|
return IN_SET(b->barriers,
|
|
BARRIER_I_ABORTED, BARRIER_THEY_ABORTED, BARRIER_WE_ABORTED);
|
|
}
|
|
|
|
static inline bool barrier_place_and_sync(Barrier *b) {
|
|
(void) barrier_place(b);
|
|
return barrier_sync(b);
|
|
}
|