libata-link: implement and use link/device iterators

Multiple links and different number of devices per link should be
considered to iterate over links and devices.  This patch implements
and uses link and device iterators - ata_port_for_each_link() and
ata_link_for_each_dev() - and ata_link_max_devices().

This change makes a lot of functions iterate over only possible
devices instead of from dev 0 to dev ATA_MAX_DEVICES.  All such
changes have been examined and nothing should be broken.

While at it, add a separating comment before device helpers to
distinguish them better from link helpers and others.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/ata/pata_pdc2027x.c b/drivers/ata/pata_pdc2027x.c
index fa78050..83c90ca 100644
--- a/drivers/ata/pata_pdc2027x.c
+++ b/drivers/ata/pata_pdc2027x.c
@@ -479,15 +479,14 @@ static void pdc2027x_set_dmamode(struct ata_port *ap, struct ata_device *adev)
  */
 static int pdc2027x_set_mode(struct ata_port *ap, struct ata_device **r_failed)
 {
-	int i;
-
-	i = ata_do_set_mode(ap, r_failed);
-	if (i < 0)
-		return i;
+	struct ata_device *dev;
+	int rc;
 
-	for (i = 0; i < ATA_MAX_DEVICES; i++) {
-		struct ata_device *dev = &ap->link.device[i];
+	rc = ata_do_set_mode(ap, r_failed);
+	if (rc < 0)
+		return rc;
 
+	ata_link_for_each_dev(dev, &ap->link) {
 		if (ata_dev_enabled(dev)) {
 
 			pdc2027x_set_piomode(ap, dev);