X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fcommon%2Fcompat%2Fpoll.c;h=9da2470d08767e4d83bc2e9a3ff0a9fc9faf38d4;hb=02c3d2c2e3b27ab0bad1207c70465f84b649c816;hp=d9acd901c0382802c136d49d9fa4a32eba22b24e;hpb=0060607b4f1947339819316b63f00e42aab2a341;p=lttng-tools.git

diff --git a/src/common/compat/poll.c b/src/common/compat/poll.c
index d9acd901c..9da2470d0 100644
--- a/src/common/compat/poll.c
+++ b/src/common/compat/poll.c
@@ -7,7 +7,6 @@
  */
 
 #define _LGPL_SOURCE
-#include <assert.h>
 #include <stdlib.h>
 #include <stdbool.h>
 
@@ -48,7 +47,7 @@ static int resize_poll_event(struct lttng_poll_event *events,
 {
 	struct epoll_event *ptr;
 
-	assert(events);
+	LTTNG_ASSERT(events);
 
 	ptr = realloc(events->events, new_size * sizeof(*ptr));
 	if (ptr == NULL) {
@@ -72,7 +71,6 @@ error:
 /*
  * Create epoll set and allocate returned events structure.
  */
-LTTNG_HIDDEN
 int compat_epoll_create(struct lttng_poll_event *events, int size, int flags)
 {
 	int ret;
@@ -125,7 +123,6 @@ error:
 /*
  * Add a fd to the epoll set with requesting events.
  */
-LTTNG_HIDDEN
 int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events)
 {
 	int ret;
@@ -173,7 +170,6 @@ error:
 /*
  * Remove a fd from the epoll set.
  */
-LTTNG_HIDDEN
 int compat_epoll_del(struct lttng_poll_event *events, int fd)
 {
 	int ret;
@@ -208,7 +204,6 @@ error:
 /*
  * Set an fd's events.
  */
-LTTNG_HIDDEN
 int compat_epoll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events)
 {
 	int ret;
@@ -250,7 +245,6 @@ error:
 /*
  * Wait on epoll set. This is a blocking call of timeout value.
  */
-LTTNG_HIDDEN
 int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
 		bool interruptible)
 {
@@ -305,7 +299,6 @@ error:
 /*
  * Setup poll set maximum size.
  */
-LTTNG_HIDDEN
 int compat_epoll_set_max_size(void)
 {
 	int ret, fd, retval = 0;
@@ -374,7 +367,7 @@ static int resize_poll_event(struct compat_poll_event_array *array,
 {
 	struct pollfd *ptr;
 
-	assert(array);
+	LTTNG_ASSERT(array);
 
 	/* Refuse to resize the array more than the max size. */
 	if (new_size > poll_max_size) {
@@ -408,7 +401,7 @@ static int update_current_events(struct lttng_poll_event *events)
 	int ret;
 	struct compat_poll_event_array *current, *wait;
 
-	assert(events);
+	LTTNG_ASSERT(events);
 
 	current = &events->current;
 	wait = &events->wait;
@@ -435,7 +428,6 @@ error:
 /*
  * Create pollfd data structure.
  */
-LTTNG_HIDDEN
 int compat_poll_create(struct lttng_poll_event *events, int size)
 {
 	struct compat_poll_event_array *current, *wait;
@@ -488,7 +480,6 @@ error:
 /*
  * Add fd to pollfd data structure with requested events.
  */
-LTTNG_HIDDEN
 int compat_poll_add(struct lttng_poll_event *events, int fd,
 		uint32_t req_events)
 {
@@ -535,7 +526,6 @@ error:
 /*
  * Modify an fd's events..
  */
-LTTNG_HIDDEN
 int compat_poll_mod(struct lttng_poll_event *events, int fd,
 		uint32_t req_events)
 {
@@ -572,7 +562,6 @@ error:
 /*
  * Remove a fd from the pollfd structure.
  */
-LTTNG_HIDDEN
 int compat_poll_del(struct lttng_poll_event *events, int fd)
 {
 	int i, count = 0, ret;
@@ -602,7 +591,7 @@ int compat_poll_del(struct lttng_poll_event *events, int fd)
 	}
 
 	/* No fd duplicate should be ever added into array. */
-	assert(current->nb_fd - 1 == count);
+	LTTNG_ASSERT(current->nb_fd - 1 == count);
 	current->nb_fd = count;
 
 	/* Resize array if needed. */
@@ -627,13 +616,11 @@ error:
 /*
  * Wait on poll() with timeout. Blocking call.
  */
-LTTNG_HIDDEN
 int compat_poll_wait(struct lttng_poll_event *events, int timeout,
 		bool interruptible)
 {
 	int ret, active_fd_count;
-	int idle_pfd_index = 0;
-	size_t i;
+	size_t pos = 0, consecutive_entries = 0, non_idle_pos;
 
 	if (events == NULL || events->current.events == NULL) {
 		ERR("poll wait arguments error");
@@ -668,34 +655,36 @@ int compat_poll_wait(struct lttng_poll_event *events, int timeout,
 	active_fd_count = ret;
 
 	/*
-	 * Swap all active pollfd structs to the beginning of the
-	 * array to emulate compat-epoll behaviour. This algorithm takes
-	 * advantage of poll's returned value and the burst nature of active
-	 * events on the file descriptors. The while loop guarantees that
-	 * idle_pfd will always point to an idle fd.
+	 * Move all active pollfd structs to the beginning of the
+	 * array to emulate compat-epoll behaviour.
 	 */
 	if (active_fd_count == events->wait.nb_fd) {
 		goto end;
 	}
-	while (idle_pfd_index < active_fd_count &&
-			events->wait.events[idle_pfd_index].revents != 0) {
-		idle_pfd_index++;
-	}
 
-	for (i = idle_pfd_index + 1; idle_pfd_index < active_fd_count;
-			i++) {
-		struct pollfd swap_pfd;
-		struct pollfd *idle_pfd = &events->wait.events[idle_pfd_index];
-		struct pollfd *current_pfd = &events->wait.events[i];
+	while (consecutive_entries != active_fd_count) {
+		struct pollfd *current = &events->wait.events[pos];
+		struct pollfd idle_entry;
 
-		if (idle_pfd->revents != 0) {
-			swap_pfd = *current_pfd;
-			*current_pfd = *idle_pfd;
-			*idle_pfd = swap_pfd;
-			idle_pfd_index++;
+		if (current->revents != 0) {
+			consecutive_entries++;
+			pos++;
+			continue;
 		}
-	}
 
+		non_idle_pos = pos;
+
+		/* Look for next non-idle entry. */
+		while (events->wait.events[++non_idle_pos].revents == 0);
+
+		/* Swap idle and non-idle entries. */
+		idle_entry = *current;
+		*current = events->wait.events[non_idle_pos];
+		events->wait.events[non_idle_pos] = idle_entry;
+
+		consecutive_entries++;
+		pos++;
+	}
 end:
 	return ret;
 
@@ -706,7 +695,6 @@ error:
 /*
  * Setup poll set maximum size.
  */
-LTTNG_HIDDEN
 int compat_poll_set_max_size(void)
 {
 	int ret, retval = 0;