[qemu.git] / include / qemu / futex.h

/*
 * Wrappers around Linux futex syscall
 *
 * Copyright Red Hat, Inc. 2017
 *
 * Author:
 *  Paolo Bonzini <[email protected]>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#ifndef QEMU_FUTEX_H
#define QEMU_FUTEX_H

#include <sys/syscall.h>
#include <linux/futex.h>

#define qemu_futex(...)              syscall(__NR_futex, __VA_ARGS__)

static inline void qemu_futex_wake(void *f, int n)
{
    qemu_futex(f, FUTEX_WAKE, n, NULL, NULL, 0);
}

static inline void qemu_futex_wait(void *f, unsigned val)
{
    while (qemu_futex(f, FUTEX_WAIT, (int) val, NULL, NULL, 0)) {
        switch (errno) {
        case EWOULDBLOCK:
            return;
        case EINTR:
            break; /* get out of switch and retry */
        default:
            abort();
        }
    }
}

#endif /* QEMU_FUTEX_H */
Commit	Line	Data
fbcc3e50 PB	1	/*
	2	* Wrappers around Linux futex syscall
	3	*
	4	* Copyright Red Hat, Inc. 2017
	5	*
	6	* Author:
	7	* Paolo Bonzini <[email protected]>
	8	*
	9	* This work is licensed under the terms of the GNU GPL, version 2 or later.
	10	* See the COPYING file in the top-level directory.
	11	*
	12	*/
	13
f3245d63 EC	14	#ifndef QEMU_FUTEX_H
	15	#define QEMU_FUTEX_H
	16
fbcc3e50 PB	17	#include <sys/syscall.h>
	18	#include <linux/futex.h>
	19
	20	#define qemu_futex(...) syscall(__NR_futex, __VA_ARGS__)
	21
	22	static inline void qemu_futex_wake(void *f, int n)
	23	{
	24	qemu_futex(f, FUTEX_WAKE, n, NULL, NULL, 0);
	25	}
	26
	27	static inline void qemu_futex_wait(void *f, unsigned val)
	28	{
	29	while (qemu_futex(f, FUTEX_WAIT, (int) val, NULL, NULL, 0)) {
	30	switch (errno) {
	31	case EWOULDBLOCK:
	32	return;
	33	case EINTR:
	34	break; /* get out of switch and retry */
	35	default:
	36	abort();
	37	}
	38	}
	39	}
f3245d63 EC	40
f3245d63 EC	41	#endif /* QEMU_FUTEX_H */