[lttng-dev] [PATCH lttng-tools v2] Change LTTNG_POLL_GETNB behaviour for poll flavor

Yannick Lamarre ylamarre at efficios.com
Thu Mar 21 11:04:48 EDT 2019

Modify LTTNG_POLL_GETNB to provide compatibility with the epoll flavor.
Since it is only used after a lttng_poll_wait call with no modification
(add, del, mod) between, this change does not modify the behaviour in
its current usage while ensuring similar API behavior between
compatibility layer implementations.

Signed-off-by: Yannick Lamarre <ylamarre at efficios.com>
 src/common/compat/poll.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/common/compat/poll.h b/src/common/compat/poll.h
index fde54ddb..5eb7ff9c 100644
--- a/src/common/compat/poll.h
+++ b/src/common/compat/poll.h
@@ -315,10 +315,12 @@ static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
  * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
  * being the index of the events array.
+ * LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
+ * current list for test compatibility purposes.
 #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
 #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
-#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->wait.nb_fd
+#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
 #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
 #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
 	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)

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