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, 10 insertions, 16 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index ec0e2638200e..3d6d5f737994 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2425,7 +2425,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
 
 static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
 {
-        if (likely(id < ATA_MAX_DEVICES))
+        if (likely(id < ata_link_max_devices(&ap->link)))
                 return &ap->link.device[id];
         return NULL;
 }
@@ -2952,21 +2952,18 @@ void ata_scsi_scan_host(struct ata_port *ap, int sync)
         int tries = 5;
         struct ata_device *last_failed_dev = NULL;
         struct ata_device *dev;
-        unsigned int i;
 
         if (ap->flags & ATA_FLAG_DISABLED)
                 return;
 
  repeat:
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
+        ata_link_for_each_dev(dev, &ap->link) {
                 struct scsi_device *sdev;
 
-                dev = &ap->link.device[i];
-
                 if (!ata_dev_enabled(dev) || dev->sdev)
                         continue;
 
-                sdev = __scsi_add_device(ap->scsi_host, 0, i, 0, NULL);
+                sdev = __scsi_add_device(ap->scsi_host, 0, dev->devno, 0, NULL);
                 if (!IS_ERR(sdev)) {
                         dev->sdev = sdev;
                         scsi_device_put(sdev);
@@ -2977,12 +2974,11 @@ void ata_scsi_scan_host(struct ata_port *ap, int sync)
          * failure occurred, scan would have failed silently.  Check
          * whether all devices are attached.
          */
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                dev = &ap->link.device[i];
+        ata_link_for_each_dev(dev, &ap->link) {
                 if (ata_dev_enabled(dev) && !dev->sdev)
                         break;
         }
-        if (i == ATA_MAX_DEVICES)
+        if (!dev)
                 return;
 
         /* we're missing some SCSI devices */
@@ -3112,7 +3108,7 @@ void ata_scsi_hotplug(struct work_struct *work)
 {
         struct ata_port *ap =
                 container_of(work, struct ata_port, hotplug_task.work);
-        int i;
+        struct ata_device *dev;
 
         if (ap->pflags & ATA_PFLAG_UNLOADING) {
                 DPRINTK("ENTER/EXIT - unloading\n");
@@ -3122,8 +3118,7 @@ void ata_scsi_hotplug(struct work_struct *work)
         DPRINTK("ENTER\n");
 
         /* unplug detached devices */
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                struct ata_device *dev = &ap->link.device[i];
+        ata_link_for_each_dev(dev, &ap->link) {
                 unsigned long flags;
 
                 if (!(dev->flags & ATA_DFLAG_DETACHED))
@@ -3176,7 +3171,7 @@ static int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel,
         spin_lock_irqsave(ap->lock, flags);
 
         if (id == SCAN_WILD_CARD) {
-                ehi->probe_mask |= (1 << ATA_MAX_DEVICES) - 1;
+                ehi->probe_mask |= (1 << ata_link_max_devices(&ap->link)) - 1;
                 ehi->action |= ATA_EH_SOFTRESET;
         } else {
                 struct ata_device *dev = ata_find_dev(ap, id);
@@ -3215,13 +3210,12 @@ void ata_scsi_dev_rescan(struct work_struct *work)
 {
         struct ata_port *ap =
                 container_of(work, struct ata_port, scsi_rescan_task);
+        struct ata_device *dev;
         unsigned long flags;
-        unsigned int i;
 
         spin_lock_irqsave(ap->lock, flags);
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                struct ata_device *dev = &ap->link.device[i];
+        ata_link_for_each_dev(dev, &ap->link) {
                 struct scsi_device *sdev = dev->sdev;
 
                 if (!ata_dev_enabled(dev) || !sdev)