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, 5 insertions, 7 deletions

diff --git a/drivers/ata/sata_sil.c b/drivers/ata/sata_sil.c
index 2ddbe4cc71e4..4c9295a49a49 100644
--- a/drivers/ata/sata_sil.c
+++ b/drivers/ata/sata_sil.c
@@ -303,22 +303,20 @@ static int sil_set_mode (struct ata_port *ap, struct ata_device **r_failed)
         struct ata_device *dev;
         void __iomem *mmio_base = host->iomap[SIL_MMIO_BAR];
         void __iomem *addr = mmio_base + sil_port[ap->port_no].xfer_mode;
-        u32 tmp, dev_mode[2];
-        unsigned int i;
+        u32 tmp, dev_mode[2] = { };
         int rc;
 
         rc = ata_do_set_mode(ap, r_failed);
         if (rc)
                 return rc;
 
-        for (i = 0; i < 2; i++) {
-                dev = &ap->link.device[i];
+        ata_link_for_each_dev(dev, &ap->link) {
                 if (!ata_dev_enabled(dev))
-                        dev_mode[i] = 0;        /* PIO0/1/2 */
+                        dev_mode[dev->devno] = 0;       /* PIO0/1/2 */
                 else if (dev->flags & ATA_DFLAG_PIO)
-                        dev_mode[i] = 1;        /* PIO3/4 */
+                        dev_mode[dev->devno] = 1;       /* PIO3/4 */
                 else
-                        dev_mode[i] = 3;        /* UDMA */
+                        dev_mode[dev->devno] = 3;       /* UDMA */
                 /* value 2 indicates MDMA */
         }