----- On Mar 19, 2019, at 5:17 PM, Yannick Lamarre ylama...@efficios.com wrote:
> This removes the need to verify for eventless file descriptors and
> mitigates risks of bug due to behaviour mismatch.
>
> Signed-off-by: Yannick Lamarre <ylama...@efficios.com>
> ---
> src/common/compat/compat-poll.c | 26 +++++++++++++++++++++++---
> 1 file changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c
> index b7c17df7..27e2002b 100644
> --- a/src/common/compat/compat-poll.c
> +++ b/src/common/compat/compat-poll.c
> @@ -292,6 +292,8 @@ error:
> int compat_poll_wait(struct lttng_poll_event *events, int timeout)
> {
> int ret;
> + int count = 0, idx;
> + struct pollfd swapfd;
The declaration scope of swapfd should be narrower (see below).
>
> if (events == NULL || events->current.events == NULL) {
> ERR("poll wait arguments error");
> @@ -324,10 +326,28 @@ int compat_poll_wait(struct lttng_poll_event *events,
> int
> timeout)
> }
>
> /*
> - * poll() should always iterate on all FDs since we handle the pollset
> in
> - * user space and after poll returns, we have to try every fd for a
> match.
> + * Swap all nonzero revents pollfd structs to the beginning of the
> array to
> + * emulate cpmpat-epoll behaviour.
cpmpat -> compat
> */
> - return events->wait.nb_fd;
> + if ( ret != events->wait.nb_fd && ret != 0) {
remove space after if (.
> + while (count < ret && events->wait.events[count].revents != 0) {
> + count += 1;
> + }
> + idx = count + 1;
> + while (count < ret) {
> + if (events->wait.events[idx].revents != 0) {
You should declare swapfd in this scope.
> + swapfd = events->wait.events[idx];
> + events->wait.events[idx] =
> events->wait.events[count];
> + events->wait.events[count] = swapfd;
> + count += 1;
> + }
> + if (idx < (events->wait.nb_fd - 1)) {
> + idx += 1;
> + }
> + }
I don't think this algorithm does what is written on the box. :-/
Thanks,
Mathieu
> + }
> +
> + return ret;
>
> error:
> return -1;
> --
> 2.11.0
>
> _______________________________________________
> lttng-dev mailing list
> lttng-dev@lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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