xref: /qemu/include/qemu/futex.h (revision f3245d63)
1 /*
2  * Wrappers around Linux futex syscall
3  *
4  * Copyright Red Hat, Inc. 2017
5  *
6  * Author:
7  *  Paolo Bonzini <pbonzini@redhat.com>
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 
14 #ifndef QEMU_FUTEX_H
15 #define QEMU_FUTEX_H
16 
17 #include <sys/syscall.h>
18 #include <linux/futex.h>
19 
20 #define qemu_futex(...)              syscall(__NR_futex, __VA_ARGS__)
21 
qemu_futex_wake(void * f,int n)22 static inline void qemu_futex_wake(void *f, int n)
23 {
24     qemu_futex(f, FUTEX_WAKE, n, NULL, NULL, 0);
25 }
26 
qemu_futex_wait(void * f,unsigned val)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 }
40 
41 #endif /* QEMU_FUTEX_H */
42