Change alarm cancel function to thread-safe.
It eliminates a race between threads using rte_alarm_cancel and
rte_alarm_set.
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski at intel.com>
Reviewed-by: Michal Jastrzebski <michalx.k.jastrzebski at intel.com>
---
lib/librte_eal/common/include/rte_alarm.h | 3 +-
lib/librte_eal/linuxapp/eal/eal_alarm.c | 68 ++++++++++++++++++-----------
2 files changed, 45 insertions(+), 26 deletions(-)
diff --git a/lib/librte_eal/common/include/rte_alarm.h
b/lib/librte_eal/common/include/rte_alarm.h
index d451522..e7cbaef 100644
--- a/lib/librte_eal/common/include/rte_alarm.h
+++ b/lib/librte_eal/common/include/rte_alarm.h
@@ -76,7 +76,8 @@ typedef void (*rte_eal_alarm_callback)(void *arg);
int rte_eal_alarm_set(uint64_t us, rte_eal_alarm_callback cb, void *cb_arg);
/**
- * Function to cancel an alarm callback which has been registered before.
+ * Function to cancel an alarm callback which has been registered before. If
+ * used outside alarm callback it wait for all callbacks to finish its
execution.
*
* @param cb_fn
* alarm callback
diff --git a/lib/librte_eal/linuxapp/eal/eal_alarm.c
b/lib/librte_eal/linuxapp/eal/eal_alarm.c
index 480f0cb..ea8dfb4 100644
--- a/lib/librte_eal/linuxapp/eal/eal_alarm.c
+++ b/lib/librte_eal/linuxapp/eal/eal_alarm.c
@@ -69,7 +69,8 @@ struct alarm_entry {
struct timeval time;
rte_eal_alarm_callback cb_fn;
void *cb_arg;
- volatile int executing;
+ volatile uint8_t executing;
+ volatile pthread_t executing_id;
};
static LIST_HEAD(alarm_list, alarm_entry) alarm_list = LIST_HEAD_INITIALIZER();
@@ -108,11 +109,13 @@ eal_alarm_callback(struct rte_intr_handle *hdl
__rte_unused,
(ap->time.tv_sec < now.tv_sec || (ap->time.tv_sec ==
now.tv_sec &&
ap->time.tv_usec <=
now.tv_usec))){
ap->executing = 1;
+ ap->executing_id = pthread_self();
rte_spinlock_unlock(&alarm_list_lk);
ap->cb_fn(ap->cb_arg);
rte_spinlock_lock(&alarm_list_lk);
+
LIST_REMOVE(ap, next);
rte_free(ap);
}
@@ -145,7 +148,7 @@ rte_eal_alarm_set(uint64_t us, rte_eal_alarm_callback
cb_fn, void *cb_arg)
if (us < 1 || us > (UINT64_MAX - US_PER_S) || cb_fn == NULL)
return -EINVAL;
- new_alarm = rte_malloc(NULL, sizeof(*new_alarm), 0);
+ new_alarm = rte_zmalloc(NULL, sizeof(*new_alarm), 0);
if (new_alarm == NULL)
return -ENOMEM;
@@ -156,7 +159,6 @@ rte_eal_alarm_set(uint64_t us, rte_eal_alarm_callback
cb_fn, void *cb_arg)
new_alarm->cb_arg = cb_arg;
new_alarm->time.tv_usec = (now.tv_usec + us) % US_PER_S;
new_alarm->time.tv_sec = now.tv_sec + ((now.tv_usec + us) / US_PER_S);
- new_alarm->executing = 0;
rte_spinlock_lock(&alarm_list_lk);
if (!handler_registered) {
@@ -202,34 +204,50 @@ rte_eal_alarm_cancel(rte_eal_alarm_callback cb_fn, void
*cb_arg)
{
struct alarm_entry *ap, *ap_prev;
int count = 0;
+ int executing;
if (!cb_fn)
return -1;
- rte_spinlock_lock(&alarm_list_lk);
- /* remove any matches at the start of the list */
- while ((ap = LIST_FIRST(&alarm_list)) != NULL &&
- cb_fn == ap->cb_fn && ap->executing == 0 &&
- (cb_arg == (void *)-1 || cb_arg == ap->cb_arg)) {
- LIST_REMOVE(ap, next);
- rte_free(ap);
- count++;
- }
- ap_prev = ap;
-
- /* now go through list, removing entries not at start */
- LIST_FOREACH(ap, &alarm_list, next) {
- /* this won't be true first time through */
- if (cb_fn == ap->cb_fn && ap->executing == 0 &&
+ do {
+ executing = 0;
+ rte_spinlock_lock(&alarm_list_lk);
+ /* remove any matches at the start of the list */
+ while ((ap = LIST_FIRST(&alarm_list)) != NULL &&
+ cb_fn == ap->cb_fn &&
(cb_arg == (void *)-1 || cb_arg == ap->cb_arg))
{
- LIST_REMOVE(ap,next);
- rte_free(ap);
- count++;
- ap = ap_prev;
+
+ if (ap->executing == 0) {
+ LIST_REMOVE(ap, next);
+ rte_free(ap);
+ count++;
+ } else {
+ if (pthread_equal(ap->executing_id,
pthread_self()) == 0)
+ executing++;
+
+ break;
+ }
}
ap_prev = ap;
- }
- rte_spinlock_unlock(&alarm_list_lk);
+
+ /* now go through list, removing entries not at start */
+ LIST_FOREACH(ap, &alarm_list, next) {
+ /* this won't be true first time through */
+ if (cb_fn == ap->cb_fn &&
+ (cb_arg == (void *)-1 || cb_arg ==
ap->cb_arg)) {
+
+ if (ap->executing == 0) {
+ LIST_REMOVE(ap,next);
+ rte_free(ap);
+ count++;
+ ap = ap_prev;
+ } else if (pthread_equal(ap->executing_id,
pthread_self()) == 0)
+ executing++;
+ }
+ ap_prev = ap;
+ }
+ rte_spinlock_unlock(&alarm_list_lk);
+ } while (executing != 0);
+
return count;
}
-
--
1.7.9.5
