diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index ac3d1204ea35..eb59f167d666 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2556,12 +2556,11 @@ int ata_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev)
 	 * host channels are not permitted to do so.
 	 */
 	if (used_dma && (ap->host->flags & ATA_HOST_SIMPLEX))
-		ap->host->simplex_claimed = 1;
+		ap->host->simplex_claimed = ap;
 
 	/* step5: chip specific finalisation */
 	if (ap->ops->post_set_mode)
 		ap->ops->post_set_mode(ap);
-
  out:
 	if (rc)
 		*r_failed_dev = dev;
@@ -3444,7 +3443,7 @@ static void ata_dev_xfermask(struct ata_device *dev)
 			       "device is on DMA blacklist, disabling DMA\n");
 	}
 
-	if ((host->flags & ATA_HOST_SIMPLEX) && host->simplex_claimed) {
+	if ((host->flags & ATA_HOST_SIMPLEX) && host->simplex_claimed != ap) {
 		xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
 		ata_dev_printk(dev, KERN_WARNING, "simplex DMA is claimed by "
 			       "other device, disabling DMA\n");
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 045fb3a72d59..3f89d13c2e9a 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -403,8 +403,7 @@ struct ata_host {
 	void			*private_data;
 	const struct ata_port_operations *ops;
 	unsigned long		flags;
-	int			simplex_claimed;	/* Keep seperate in case we
-							   ever need to do this locked */
+	struct ata_port		*simplex_claimed;	/* channel owning the DMA */
 	struct ata_port		*ports[0];
 };