Module: xenomai-forge
Branch: master
Commit: dad32967e94f5fff4edcffd4a78300442d79f0b9
URL:
http://git.xenomai.org/?p=xenomai-forge.git;a=commit;h=dad32967e94f5fff4edcffd4a78300442d79f0b9
Author: Philippe Gerum <r...@xenomai.org>
Date: Tue Dec 13 15:53:03 2011 +0100
kernel/cobalt: introduce monotonic clock-based sem_timedwait()
POSIX mandates that timed waits on semaphores be based on
CLOCK_REALTIME. We introduce a non-standard variant allowing
CLOCK_MONOTONIC to be used instead, if SEM_RAWCLOCK is mentioned in
the creation flags passed to sem_init_np().
---
include/cobalt/semaphore.h | 1 +
kernel/cobalt/sem.c | 36 ++++++++++++++++++++----------------
2 files changed, 21 insertions(+), 16 deletions(-)
diff --git a/include/cobalt/semaphore.h b/include/cobalt/semaphore.h
index c7a29c3..312e73a 100644
--- a/include/cobalt/semaphore.h
+++ b/include/cobalt/semaphore.h
@@ -110,6 +110,7 @@ COBALT_DECL(int, sem_unlink(const char *name));
#define SEM_PSHARED 0x4
#define SEM_REPORT 0x8
#define SEM_WARNDEL 0x10
+#define SEM_RAWCLOCK 0x20
int sem_init_np(sem_t *sem,
int flags,
diff --git a/kernel/cobalt/sem.c b/kernel/cobalt/sem.c
index 6b1918c..e650fac 100644
--- a/kernel/cobalt/sem.c
+++ b/kernel/cobalt/sem.c
@@ -521,26 +521,27 @@ static int sem_trywait(cobalt_sem_t *sem)
static inline int
sem_timedwait_internal(cobalt_sem_t *sem, int timed, xnticks_t to)
{
- xnthread_t *cur;
- int err;
-
- cur = xnpod_current_thread();
+ xntmode_t tmode;
+ xnflags_t info;
+ int ret;
- if ((err = sem_trywait_internal(sem)) != -EAGAIN)
- return err;
+ ret = sem_trywait_internal(sem);
+ if (ret != -EAGAIN)
+ return ret;
- if (timed)
- xnsynch_sleep_on(&sem->synchbase, to, XN_REALTIME);
- else
- xnsynch_sleep_on(&sem->synchbase, XN_INFINITE, XN_RELATIVE);
+ if (timed) {
+ tmode = sem->flags & SEM_RAWCLOCK ? XN_ABSOLUTE : XN_REALTIME;
+ info = xnsynch_sleep_on(&sem->synchbase, to, tmode);
+ } else
+ info = xnsynch_sleep_on(&sem->synchbase, XN_INFINITE,
XN_RELATIVE);
- if (xnthread_test_info(cur, XNRMID))
+ if (info & XNRMID)
return -EINVAL;
- if (xnthread_test_info(cur, XNBREAK))
+ if (info & XNBREAK)
return -EINTR;
- if (xnthread_test_info(cur, XNTIMEO))
+ if (info & XNTIMEO)
return -ETIMEDOUT;
return 0;
@@ -599,8 +600,10 @@ static int sem_wait(cobalt_sem_t *sem)
*
* @param sm the semaphore to be decremented;
*
- * @param abs_timeout the timeout, expressed as an absolute value of the
- * CLOCK_REALTIME clock.
+ * @param abs_timeout the timeout, expressed as an absolute value of
+ * the relevant clock for the semaphore, either CLOCK_MONOTONIC if
+ * SEM_RAWCLOCK was mentioned via sem_init_np(), or CLOCK_REALTIME
+ * otherwise.
*
* @retval 0 on success;
* @retval -1 with @a errno set if:
@@ -987,7 +990,8 @@ int cobalt_sem_init_np(struct __shadow_sem __user *u_sem,
if (__xn_safe_copy_from_user(&sm, u_sem, sizeof(sm)))
return -EFAULT;
- if (flags & ~(SEM_FIFO|SEM_PULSE|SEM_PSHARED|SEM_REPORT|SEM_WARNDEL))
+ if (flags & ~(SEM_FIFO|SEM_PULSE|SEM_PSHARED|\
+ SEM_REPORT|SEM_WARNDEL|SEM_RAWCLOCK))
return -EINVAL;
err = do_sem_init(&sm, flags, value);
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