diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 4ba967d65cf9..3b2c9289dccb 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -833,7 +833,7 @@ static int parse_rbd_opts_token(char *c, void *private)
 		pctx->opts->queue_depth = intval;
 		break;
 	case Opt_alloc_size:
-		if (intval < 1) {
+		if (intval < SECTOR_SIZE) {
 			pr_err("alloc_size out of range\n");
 			return -EINVAL;
 		}
@@ -4203,12 +4203,12 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 	q->limits.max_sectors = queue_max_hw_sectors(q);
 	blk_queue_max_segments(q, USHRT_MAX);
 	blk_queue_max_segment_size(q, UINT_MAX);
-	blk_queue_io_min(q, objset_bytes);
-	blk_queue_io_opt(q, objset_bytes);
+	blk_queue_io_min(q, rbd_dev->opts->alloc_size);
+	blk_queue_io_opt(q, rbd_dev->opts->alloc_size);
 
 	if (rbd_dev->opts->trim) {
 		blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
-		q->limits.discard_granularity = objset_bytes;
+		q->limits.discard_granularity = rbd_dev->opts->alloc_size;
 		blk_queue_max_discard_sectors(q, objset_bytes >> SECTOR_SHIFT);
 		blk_queue_max_write_zeroes_sectors(q, objset_bytes >> SECTOR_SHIFT);
 	}