[PATCH v3 2/4] ibacm: Calculate correct tv_nsec value in event_wait()

Michael J. Ruhl
2017-11-14T16:43:32Z

From: Michael J. Ruhl <michael.j.ruhl-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

The event_wait() function calculates a tv_nsec value based on the
given timeout. If the tv_nsec value calculation ends ups larger
than 1 second, the pthread_cond_timedwait() will return EINVAL,
and will not wait.

This causes the retry loop to spin (busy wait) until the actual
timeout occurs.

Ensure that the tv_nsec value is less than 1 second.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
ibacm/linux/osd.h | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/ibacm/linux/osd.h b/ibacm/linux/osd.h
index 95713e6..eabf5ed 100644
--- a/ibacm/linux/osd.h
+++ b/ibacm/linux/osd.h
@@ -92,6 +92,7 @@ static inline void event_init(event_t *e)
pthread_mutex_init(&e->mutex, NULL);
}
#define event_signal(e) pthread_cond_signal(&(e)->cond)
+#define ONE_SEC_IN_NSEC 1000000000ULL
static inline int event_wait(event_t *e, int timeout)
{
struct timeval curtime;
@@ -101,6 +102,10 @@ static inline int event_wait(event_t *e, int timeout)
gettimeofday(&curtime, NULL);
wait.tv_sec = curtime.tv_sec + ((unsigned) timeout) / 1000;
wait.tv_nsec = (curtime.tv_usec + (((unsigned) timeout) % 1000) * 1000) * 1000;
+ if (wait.tv_nsec > ONE_SEC_IN_NSEC) {
+ wait.tv_sec++;
+ wait.tv_nsec -= ONE_SEC_IN_NSEC;
+ }
pthread_mutex_lock(&e->mutex);
ret = pthread_cond_timedwait(&e->cond, &e->mutex, &wait);
pthread_mutex_unlock(&e->mutex);