sbitmap: warn if using smaller shallow depth than was setup

Make sure the user passed the right value to
sbitmap_queue_min_shallow_depth().
Acked-by: NPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

lib/sbitmap.c

@@ -402,6 +402,8 @@ int __sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
 	unsigned int hint, depth;
 	int nr;
 
+	WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
+
 	hint = this_cpu_read(*sbq->alloc_hint);
 	depth = READ_ONCE(sbq->sb.depth);
 	if (unlikely(hint >= depth)) {