ioq: Check for io_uring_register_iowq_max_workers() before using it

This allows us to build against liburing as old as version 2.0, which is
apparently shipped by the latest Amazon Linux distribution.

Fixes: https://github.com/tavianator/bfs/issues/147

1 files changed, 3 insertions, 0 deletions

diff --git a/src/ioq.c b/src/ioq.c
index f936ff8..be5b758 100644
--- a/src/ioq.c
+++ b/src/ioq.c
@@ -878,6 +878,7 @@ static int ioq_ring_init(struct ioq *ioq, struct ioq_thread *thread) {
 		return -1;
 	}
 
+#if BFS_HAS_IO_URING_MAX_WORKERS
 	// Limit the number of io_uring workers
 	unsigned int values[] = {
 		ioq->nthreads, // [IO_WQ_BOUND]
@@ -886,6 +887,8 @@ static int ioq_ring_init(struct ioq *ioq, struct ioq_thread *thread) {
 	io_uring_register_iowq_max_workers(&thread->ring, values);
 #endif
 
+#endif // BFS_WITH_LIBURING
+
 	return 0;
 }