[PATCH] libata: add ata_dev_pair helper

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 19 insertions, 0 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index d8f77f2a5af1..909568f7a72a 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1576,6 +1576,23 @@ void sata_phy_reset(struct ata_port *ap)
 }
 
 /**
+ *      ata_dev_pair            -       return other device on cable
+ *      @ap: port
+ *      @adev: device
+ *
+ *      Obtain the other device on the same cable, or if none is
+ *      present NULL is returned
+ */
+ 
+struct ata_device *ata_dev_pair(struct ata_port *ap, struct ata_device *adev)
+{
+        struct ata_device *pair = &ap->device[1 - adev->devno];
+        if (!ata_dev_present(pair))
+                return NULL;
+        return pair;
+}
+
+/**
  *      ata_port_disable - Disable port.
  *      @ap: Port to be disabled.
  *
diff --git a/include/linux/libata.h b/include/linux/libata.h
index c52f13498556..80c2339da67d 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -573,6 +573,8 @@ extern int ata_std_bios_param(struct scsi_device *sdev,
                               struct block_device *bdev,
                               sector_t capacity, int geom[]);
 extern int ata_scsi_slave_config(struct scsi_device *sdev);
+extern struct ata_device *ata_dev_pair(struct ata_port *ap, 
+                                       struct ata_device *adev);
 
 /*
  * Timing helpers