diff --git a/fs/io_uring.c b/fs/io_uring.c
index b35300e..f65f85d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -338,7 +338,7 @@
 	tail = ctx->cached_cq_tail;
 	/* See comment at the top of the file */
 	smp_rmb();
-	if (tail + 1 == READ_ONCE(ring->r.head))
+	if (tail - READ_ONCE(ring->r.head) == ring->ring_entries)
 		return NULL;
 
 	ctx->cached_cq_tail++;