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, 3 insertions, 4 deletions

diff --git a/drivers/ata/ata_generic.c b/drivers/ata/ata_generic.c
index b5e390ff5bd8..44328a16075c 100644
--- a/drivers/ata/ata_generic.c
+++ b/drivers/ata/ata_generic.c
@@ -46,21 +46,20 @@
 static int generic_set_mode(struct ata_port *ap, struct ata_device **unused)
 {
         int dma_enabled = 0;
-        int i;
+        struct ata_device *dev;
 
         /* Bits 5 and 6 indicate if DMA is active on master/slave */
         if (ap->ioaddr.bmdma_addr)
                 dma_enabled = ioread8(ap->ioaddr.bmdma_addr + ATA_DMA_STATUS);
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                struct ata_device *dev = &ap->link.device[i];
+        ata_link_for_each_dev(dev, &ap->link) {
                 if (ata_dev_enabled(dev)) {
                         /* We don't really care */
                         dev->pio_mode = XFER_PIO_0;
                         dev->dma_mode = XFER_MW_DMA_0;
                         /* We do need the right mode information for DMA or PIO
                            and this comes from the current configuration flags */
-                        if (dma_enabled & (1 << (5 + i))) {
+                        if (dma_enabled & (1 << (5 + dev->devno))) {
                                 ata_id_to_dma_mode(dev, XFER_MW_DMA_0);
                                 dev->flags &= ~ATA_DFLAG_PIO;
                         } else {