diff --git a/block/blk-mq-dma.c b/block/blk-mq-dma.c
index 88fd9cbc951f..e0e7a18790b5 100644
--- a/block/blk-mq-dma.c
+++ b/block/blk-mq-dma.c
@@ -181,6 +181,8 @@ static bool blk_dma_map_iter_start(struct request *req, struct device *dma_dev,
 	switch (pci_p2pdma_state(&iter->p2pdma, dma_dev,
 				 phys_to_page(vec.paddr))) {
 	case PCI_P2PDMA_MAP_BUS_ADDR:
+		/* don't leave the state of an earlier mapping to the caller */
+		memset(state, 0, sizeof(*state));
 		return blk_dma_map_bus(iter, &vec);
 	case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
 		/*