2 files changed, 3 insertions, 5 deletions

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];
 };