libata: fix device iteration bugs

There were several places where only enabled devices should be
iterated over but device enabledness wasn't checked.

* IDENTIFY data 40 wire check in cable_is_40wire()
* xfer_mode/ncq_enabled saving in ata_scsi_error()
* DUBIOUS_XFER handling in ata_set_mode()

While at it, reformat comments in cable_is_40wire().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 19 insertions, 15 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 8cb0b360bfd..97df4807a08 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4156,29 +4156,33 @@ static int cable_is_40wire(struct ata_port *ap)
         struct ata_link *link;
         struct ata_device *dev;
 
-        /* If the controller thinks we are 40 wire, we are */
+        /* If the controller thinks we are 40 wire, we are. */
         if (ap->cbl == ATA_CBL_PATA40)
                 return 1;
-        /* If the controller thinks we are 80 wire, we are */
+
+        /* If the controller thinks we are 80 wire, we are. */
         if (ap->cbl == ATA_CBL_PATA80 || ap->cbl == ATA_CBL_SATA)
                 return 0;
-        /* If the system is known to be 40 wire short cable (eg laptop),
-           then we allow 80 wire modes even if the drive isn't sure */
+
+        /* If the system is known to be 40 wire short cable (eg
+         * laptop), then we allow 80 wire modes even if the drive
+         * isn't sure.
+         */
         if (ap->cbl == ATA_CBL_PATA40_SHORT)
                 return 0;
-        /* If the controller doesn't know we scan
-
-           - Note: We look for all 40 wire detects at this point.
-             Any 80 wire detect is taken to be 80 wire cable
-             because
-             - In many setups only the one drive (slave if present)
-               will give a valid detect
-             - If you have a non detect capable drive you don't
-               want it to colour the choice
-        */
+
+        /* If the controller doesn't know, we scan.
+         *
+         * Note: We look for all 40 wire detects at this point.  Any
+         *       80 wire detect is taken to be 80 wire cable because
+         * - in many setups only the one drive (slave if present) will
+         *   give a valid detect
+         * - if you have a non detect capable drive you don't want it
+         *   to colour the choice
+         */
         ata_port_for_each_link(link, ap) {
                 ata_link_for_each_dev(dev, link) {
-                        if (!ata_is_40wire(dev))
+                        if (ata_dev_enabled(dev) && !ata_is_40wire(dev))
                                 return 0;
                 }
         }