songvec: avoid holding nr_lock during free(3)

We only need to lock sv->nr changes to prevent traversals ( why
it's called "nr_lock").  free(3) is a "slow" function on my
system; so we can avoid unnecessarily holding a lock long for
longer than needed.

1 files changed, 5 insertions, 3 deletions

diff --git a/src/songvec.c b/src/songvec.c
index ce04a4373..3d512e917 100644
--- a/src/songvec.c
+++ b/src/songvec.c
@@ -48,10 +48,12 @@ int songvec_delete(struct songvec *sv, const struct mpd_song *del)
 	for (i = sv->nr; --i >= 0; ) {
 		if (sv->base[i] != del)
 			continue;
-		/* we _don't_ call freeSong() here */
+		/* we _don't_ call song_free() here */
 		if (!--sv->nr) {
+			pthread_mutex_unlock(&nr_lock);
 			free(sv->base);
 			sv->base = NULL;
+			return i;
 		} else {
 			memmove(&sv->base[i], &sv->base[i + 1],
 				(sv->nr - i + 1) * sizeof(struct mpd_song *));
@@ -76,12 +78,12 @@ void songvec_add(struct songvec *sv, struct mpd_song *add)
 void songvec_destroy(struct songvec *sv)
 {
 	pthread_mutex_lock(&nr_lock);
+	sv->nr = 0;
+	pthread_mutex_unlock(&nr_lock);
 	if (sv->base) {
 		free(sv->base);
 		sv->base = NULL;
 	}
-	sv->nr = 0;
-	pthread_mutex_unlock(&nr_lock);
 }
 
 int songvec_for_each(const struct songvec *sv,