diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index e1346cd..1c1a7ca 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2622,8 +2622,11 @@
 
 	dma_address = dma_map_single(ap->host_set->dev, qc->buf_virt,
 				     sg->length, dir);
-	if (dma_mapping_error(dma_address))
+	if (dma_mapping_error(dma_address)) {
+		/* restore sg */
+		sg->length += qc->pad_len;
 		return -1;
+	}
 
 	sg_dma_address(sg) = dma_address;
 	sg_dma_len(sg) = sg->length;
@@ -2694,8 +2697,11 @@
 
 	dir = qc->dma_dir;
 	n_elem = dma_map_sg(ap->host_set->dev, sg, qc->n_elem, dir);
-	if (n_elem < 1)
+	if (n_elem < 1) {
+		/* restore last sg */
+		lsg->length += qc->pad_len;
 		return -1;
+	}
 
 	DPRINTK("%d sg elements mapped\n", n_elem);