13 files changed, 134 insertions, 148 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 {
diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index 0023ac4ff496..43af2e06d446 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -509,7 +509,7 @@ int ata_acpi_on_suspend(struct ata_port *ap)
  */
 void ata_acpi_on_resume(struct ata_port *ap)
 {
-        int i;
+        struct ata_device *dev;
 
         if (ap->acpi_handle && (ap->pflags & ATA_PFLAG_GTM_VALID)) {
                 BUG_ON(ap->flags & ATA_FLAG_ACPI_SATA);
@@ -519,8 +519,8 @@ void ata_acpi_on_resume(struct ata_port *ap)
         }
 
         /* schedule _GTF */
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                ap->link.device[i].flags |= ATA_DFLAG_ACPI_PENDING;
+        ata_link_for_each_dev(dev, &ap->link)
+                dev->flags |= ATA_DFLAG_ACPI_PENDING;
 }
 
 /**
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index dd2de485124a..f30c4771b3af 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2105,21 +2105,19 @@ int ata_bus_probe(struct ata_port *ap)
 {
         unsigned int classes[ATA_MAX_DEVICES];
         int tries[ATA_MAX_DEVICES];
-        int i, rc;
+        int rc;
         struct ata_device *dev;
 
         ata_port_probe(ap);
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                tries[i] = ATA_PROBE_MAX_TRIES;
+        ata_link_for_each_dev(dev, &ap->link)
+                tries[dev->devno] = ATA_PROBE_MAX_TRIES;
 
  retry:
         /* reset and determine device classes */
         ap->ops->phy_reset(ap);
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                dev = &ap->link.device[i];
-
+        ata_link_for_each_dev(dev, &ap->link) {
                 if (!(ap->flags & ATA_FLAG_DISABLED) &&
                     dev->class != ATA_DEV_UNKNOWN)
                         classes[dev->devno] = dev->class;
@@ -2134,18 +2132,16 @@ int ata_bus_probe(struct ata_port *ap)
         /* after the reset the device state is PIO 0 and the controller
            state is undefined. Record the mode */
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                ap->link.device[i].pio_mode = XFER_PIO_0;
+        ata_link_for_each_dev(dev, &ap->link)
+                dev->pio_mode = XFER_PIO_0;
 
         /* read IDENTIFY page and configure devices. We have to do the identify
            specific sequence bass-ackwards so that PDIAG- is released by
            the slave device */
 
-        for (i = ATA_MAX_DEVICES - 1; i >=  0; i--) {
-                dev = &ap->link.device[i];
-
-                if (tries[i])
-                        dev->class = classes[i];
+        ata_link_for_each_dev(dev, &ap->link) {
+                if (tries[dev->devno])
+                        dev->class = classes[dev->devno];
 
                 if (!ata_dev_enabled(dev))
                         continue;
@@ -2163,8 +2159,7 @@ int ata_bus_probe(struct ata_port *ap)
         /* After the identify sequence we can now set up the devices. We do
            this in the normal order so that the user doesn't get confused */
 
-        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))
                         continue;
 
@@ -2180,8 +2175,8 @@ int ata_bus_probe(struct ata_port *ap)
         if (rc)
                 goto fail;
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                if (ata_dev_enabled(&ap->link.device[i]))
+        ata_link_for_each_dev(dev, &ap->link)
+                if (ata_dev_enabled(dev))
                         return 0;
 
         /* no device present, disable port */
@@ -2803,16 +2798,14 @@ static int ata_dev_set_mode(struct ata_device *dev)
 
 int ata_do_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev)
 {
+        struct ata_link *link = &ap->link;
         struct ata_device *dev;
-        int i, rc = 0, used_dma = 0, found = 0;
-
+        int rc = 0, used_dma = 0, found = 0;
 
         /* step 1: calculate xfer_mask */
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
+        ata_link_for_each_dev(dev, link) {
                 unsigned int pio_mask, dma_mask;
 
-                dev = &ap->link.device[i];
-
                 if (!ata_dev_enabled(dev))
                         continue;
 
@@ -2831,8 +2824,7 @@ int ata_do_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev)
                 goto out;
 
         /* step 2: always set host PIO timings */
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                dev = &ap->link.device[i];
+        ata_link_for_each_dev(dev, link) {
                 if (!ata_dev_enabled(dev))
                         continue;
 
@@ -2849,9 +2841,7 @@ int ata_do_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev)
         }
 
         /* step 3: set host DMA timings */
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                dev = &ap->link.device[i];
-
+        ata_link_for_each_dev(dev, link) {
                 if (!ata_dev_enabled(dev) || !dev->dma_mode)
                         continue;
 
@@ -2862,9 +2852,7 @@ int ata_do_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev)
         }
 
         /* step 4: update devices' xfer mode */
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                dev = &ap->link.device[i];
-
+        ata_link_for_each_dev(dev, link) {
                 /* don't update suspended devices' xfer mode */
                 if (!ata_dev_enabled(dev))
                         continue;
@@ -6113,6 +6101,7 @@ struct ata_port *ata_port_alloc(struct ata_host *host)
 
         ap->link.ap = ap;
 
+        /* can't use iterator, ap isn't initialized yet */
         for (i = 0; i < ATA_MAX_DEVICES; i++) {
                 struct ata_device *dev = &ap->link.device[i];
                 dev->link = &ap->link;
@@ -6453,7 +6442,8 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
                         /* kick EH for boot probing */
                         spin_lock_irqsave(ap->lock, flags);
 
-                        ehi->probe_mask = (1 << ATA_MAX_DEVICES) - 1;
+                        ehi->probe_mask =
+                                (1 << ata_link_max_devices(&ap->link)) - 1;
                         ehi->action |= ATA_EH_SOFTRESET;
                         ehi->flags |= ATA_EHI_NO_AUTOPSY | ATA_EHI_QUIET;
 
@@ -6551,7 +6541,7 @@ int ata_host_activate(struct ata_host *host, int irq,
 void ata_port_detach(struct ata_port *ap)
 {
         unsigned long flags;
-        int i;
+        struct ata_device *dev;
 
         if (!ap->ops->error_handler)
                 goto skip_eh;
@@ -6568,8 +6558,8 @@ void ata_port_detach(struct ata_port *ap)
          */
         spin_lock_irqsave(ap->lock, flags);
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                ata_dev_disable(&ap->link.device[i]);
+        ata_link_for_each_dev(dev, &ap->link)
+                ata_dev_disable(dev);
 
         spin_unlock_irqrestore(ap->lock, flags);
 
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index e2681f56ed44..8c37ec0bbf6c 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -200,23 +200,24 @@ static unsigned int ata_eh_dev_action(struct ata_device *dev)
         return ehc->i.action | ehc->i.dev_action[dev->devno];
 }
 
-static void ata_eh_clear_action(struct ata_device *dev,
+static void ata_eh_clear_action(struct ata_link *link, struct ata_device *dev,
                                 struct ata_eh_info *ehi, unsigned int action)
 {
-        int i;
+        struct ata_device *tdev;
 
         if (!dev) {
                 ehi->action &= ~action;
-                for (i = 0; i < ATA_MAX_DEVICES; i++)
-                        ehi->dev_action[i] &= ~action;
+                ata_link_for_each_dev(tdev, link)
+                        ehi->dev_action[tdev->devno] &= ~action;
         } else {
                 /* doesn't make sense for port-wide EH actions */
                 WARN_ON(!(action & ATA_EH_PERDEV_MASK));
 
                 /* break ehi->action into ehi->dev_action */
                 if (ehi->action & action) {
-                        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                                ehi->dev_action[i] |= ehi->action & action;
+                        ata_link_for_each_dev(tdev, link)
+                                ehi->dev_action[tdev->devno] |=
+                                        ehi->action & action;
                         ehi->action &= ~action;
                 }
 
@@ -922,7 +923,8 @@ void ata_eh_qc_retry(struct ata_queued_cmd *qc)
  */
 static void ata_eh_detach_dev(struct ata_device *dev)
 {
-        struct ata_port *ap = dev->link->ap;
+        struct ata_link *link = dev->link;
+        struct ata_port *ap = link->ap;
         unsigned long flags;
 
         ata_dev_disable(dev);
@@ -937,8 +939,8 @@ static void ata_eh_detach_dev(struct ata_device *dev)
         }
 
         /* clear per-dev EH actions */
-        ata_eh_clear_action(dev, &dev->link->eh_info, ATA_EH_PERDEV_MASK);
-        ata_eh_clear_action(dev, &dev->link->eh_context.i, ATA_EH_PERDEV_MASK);
+        ata_eh_clear_action(link, dev, &link->eh_info, ATA_EH_PERDEV_MASK);
+        ata_eh_clear_action(link, dev, &link->eh_context.i, ATA_EH_PERDEV_MASK);
 
         spin_unlock_irqrestore(ap->lock, flags);
 }
@@ -978,7 +980,7 @@ static void ata_eh_about_to_do(struct ata_port *ap, struct ata_device *dev,
                 ehi->flags &= ~ATA_EHI_RESET_MODIFIER_MASK;
         }
 
-        ata_eh_clear_action(dev, ehi, action);
+        ata_eh_clear_action(&ap->link, dev, ehi, action);
 
         if (!(ehc->i.flags & ATA_EHI_QUIET))
                 ap->pflags |= ATA_PFLAG_RECOVERED;
@@ -1009,7 +1011,7 @@ static void ata_eh_done(struct ata_port *ap, struct ata_device *dev,
                 ehc->i.flags &= ~ATA_EHI_RESET_MODIFIER_MASK;
         }
 
-        ata_eh_clear_action(dev, &ehc->i, action);
+        ata_eh_clear_action(&ap->link, dev, &ehc->i, action);
 }
 
 /**
@@ -1736,10 +1738,11 @@ static void ata_eh_report(struct ata_port *ap)
 static int ata_do_reset(struct ata_port *ap, ata_reset_fn_t reset,
                         unsigned int *classes, unsigned long deadline)
 {
-        int i, rc;
+        struct ata_device *dev;
+        int rc;
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                classes[i] = ATA_DEV_UNKNOWN;
+        ata_link_for_each_dev(dev, &ap->link)
+                classes[dev->devno] = ATA_DEV_UNKNOWN;
 
         rc = reset(ap, classes, deadline);
         if (rc)
@@ -1749,14 +1752,16 @@ static int ata_do_reset(struct ata_port *ap, ata_reset_fn_t reset,
          * is complete and convert all ATA_DEV_UNKNOWN to
          * ATA_DEV_NONE.
          */
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                if (classes[i] != ATA_DEV_UNKNOWN)
+        ata_link_for_each_dev(dev, &ap->link)
+                if (classes[dev->devno] != ATA_DEV_UNKNOWN)
                         break;
 
-        if (i < ATA_MAX_DEVICES)
-                for (i = 0; i < ATA_MAX_DEVICES; i++)
-                        if (classes[i] == ATA_DEV_UNKNOWN)
-                                classes[i] = ATA_DEV_NONE;
+        if (dev) {
+                ata_link_for_each_dev(dev, &ap->link) {
+                        if (classes[dev->devno] == ATA_DEV_UNKNOWN)
+                                classes[dev->devno] = ATA_DEV_NONE;
+                }
+        }
 
         return 0;
 }
@@ -1781,10 +1786,11 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
         unsigned int *classes = ehc->classes;
         int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
         int try = 0;
+        struct ata_device *dev;
         unsigned long deadline;
         unsigned int action;
         ata_reset_fn_t reset;
-        int i, rc;
+        int rc;
 
         /* about to reset */
         ata_eh_about_to_do(ap, NULL, ehc->i.action & ATA_EH_RESET_MASK);
@@ -1808,8 +1814,8 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
                                                 "port disabled. ignoring.\n");
                                 ehc->i.action &= ~ATA_EH_RESET_MASK;
 
-                                for (i = 0; i < ATA_MAX_DEVICES; i++)
-                                        classes[i] = ATA_DEV_NONE;
+                                ata_link_for_each_dev(dev, &ap->link)
+                                        classes[dev->devno] = ATA_DEV_NONE;
 
                                 rc = 0;
                         } else
@@ -1826,8 +1832,8 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
                 reset = softreset;
         else {
                 /* prereset told us not to reset, bang classes and return */
-                for (i = 0; i < ATA_MAX_DEVICES; i++)
-                        classes[i] = ATA_DEV_NONE;
+                ata_link_for_each_dev(dev, &ap->link)
+                        classes[dev->devno] = ATA_DEV_NONE;
                 rc = 0;
                 goto out;
         }
@@ -1908,8 +1914,8 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
                 /* After the reset, the device state is PIO 0 and the
                  * controller state is undefined.  Record the mode.
                  */
-                for (i = 0; i < ATA_MAX_DEVICES; i++)
-                        ap->link.device[i].pio_mode = XFER_PIO_0;
+                ata_link_for_each_dev(dev, &ap->link)
+                        dev->pio_mode = XFER_PIO_0;
 
                 /* record current link speed */
                 if (sata_scr_read(ap, SCR_STATUS, &sstatus) == 0)
@@ -1935,7 +1941,7 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
         struct ata_device *dev;
         unsigned int new_mask = 0;
         unsigned long flags;
-        int i, rc = 0;
+        int rc = 0;
 
         DPRINTK("ENTER\n");
 
@@ -1943,11 +1949,9 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
          * be done backwards such that PDIAG- is released by the slave
          * device before the master device is identified.
          */
-        for (i = ATA_MAX_DEVICES - 1; i >= 0; i--) {
-                unsigned int action, readid_flags = 0;
-
-                dev = &ap->link.device[i];
-                action = ata_eh_dev_action(dev);
+        ata_link_for_each_dev_reverse(dev, &ap->link) {
+                unsigned int action = ata_eh_dev_action(dev);
+                unsigned int readid_flags = 0;
 
                 if (ehc->i.flags & ATA_EHI_DID_RESET)
                         readid_flags |= ATA_READID_POSTRESET;
@@ -1981,7 +1985,7 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
                                              dev->id);
                         switch (rc) {
                         case 0:
-                                new_mask |= 1 << i;
+                                new_mask |= 1 << dev->devno;
                                 break;
                         case -ENOENT:
                                 /* IDENTIFY was issued to non-existent
@@ -2005,10 +2009,8 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
         /* Configure new devices forward such that user doesn't see
          * device detection messages backwards.
          */
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                dev = &ap->link.device[i];
-
-                if (!(new_mask & (1 << i)))
+        ata_link_for_each_dev(dev, &ap->link) {
+                if (!(new_mask & (1 << dev->devno)))
                         continue;
 
                 ehc->i.flags |= ATA_EHI_PRINTINFO;
@@ -2035,20 +2037,22 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
 
 static int ata_port_nr_enabled(struct ata_port *ap)
 {
-        int i, cnt = 0;
+        struct ata_device *dev;
+        int cnt = 0;
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                if (ata_dev_enabled(&ap->link.device[i]))
+        ata_link_for_each_dev(dev, &ap->link)
+                if (ata_dev_enabled(dev))
                         cnt++;
         return cnt;
 }
 
 static int ata_port_nr_vacant(struct ata_port *ap)
 {
-        int i, cnt = 0;
+        struct ata_device *dev;
+        int cnt = 0;
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                if (ap->link.device[i].class == ATA_DEV_UNKNOWN)
+        ata_link_for_each_dev(dev, &ap->link)
+                if (dev->class == ATA_DEV_UNKNOWN)
                         cnt++;
         return cnt;
 }
@@ -2056,7 +2060,7 @@ static int ata_port_nr_vacant(struct ata_port *ap)
 static int ata_eh_skip_recovery(struct ata_port *ap)
 {
         struct ata_eh_context *ehc = &ap->link.eh_context;
-        int i;
+        struct ata_device *dev;
 
         /* thaw frozen port, resume link and recover failed devices */
         if ((ap->pflags & ATA_PFLAG_FROZEN) ||
@@ -2064,9 +2068,7 @@ static int ata_eh_skip_recovery(struct ata_port *ap)
                 return 0;
 
         /* skip if class codes for all vacant slots are ATA_DEV_NONE */
-        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 (dev->class == ATA_DEV_UNKNOWN &&
                     ehc->classes[dev->devno] != ATA_DEV_NONE)
                         return 0;
@@ -2153,19 +2155,18 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 {
         struct ata_eh_context *ehc = &ap->link.eh_context;
         struct ata_device *dev;
-        int i, rc;
+        int rc;
 
         DPRINTK("ENTER\n");
 
         /* prep for recovery */
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                dev = &ap->link.device[i];
-
+        ata_link_for_each_dev(dev, &ap->link) {
                 ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
 
                 /* collect port action mask recorded in dev actions */
-                ehc->i.action |= ehc->i.dev_action[i] & ~ATA_EH_PERDEV_MASK;
-                ehc->i.dev_action[i] &= ATA_EH_PERDEV_MASK;
+                ehc->i.action |=
+                        ehc->i.dev_action[dev->devno] & ~ATA_EH_PERDEV_MASK;
+                ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;
 
                 /* process hotplug request */
                 if (dev->flags & ATA_DFLAG_DETACH)
@@ -2192,8 +2193,8 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
         if (ata_eh_skip_recovery(ap))
                 ehc->i.action = 0;
 
-        for (i = 0; i < ATA_MAX_DEVICES; i++)
-                ehc->classes[i] = ATA_DEV_UNKNOWN;
+        ata_link_for_each_dev(dev, &ap->link)
+                ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
 
         /* reset */
         if (ehc->i.action & ATA_EH_RESET_MASK) {
@@ -2241,8 +2242,8 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 
  out:
         if (rc) {
-                for (i = 0; i < ATA_MAX_DEVICES; i++)
-                        ata_dev_disable(&ap->link.device[i]);
+                ata_link_for_each_dev(dev, &ap->link);
+                        ata_dev_disable(dev);
         }
 
         DPRINTK("EXIT, rc=%d\n", rc);
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)
diff --git a/drivers/ata/pata_it821x.c b/drivers/ata/pata_it821x.c
index ece1a28f0a4a..088eb1d23761 100644
--- a/drivers/ata/pata_it821x.c
+++ b/drivers/ata/pata_it821x.c
@@ -461,10 +461,9 @@ static unsigned int it821x_passthru_qc_issue_prot(struct ata_queued_cmd *qc)
 
 static int it821x_smart_set_mode(struct ata_port *ap, struct ata_device **unused)
 {
-        int i;
+        struct ata_device *dev;
 
-        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;
diff --git a/drivers/ata/pata_ixp4xx_cf.c b/drivers/ata/pata_ixp4xx_cf.c
index 3e2b8ce5fa37..7db315a9baad 100644
--- a/drivers/ata/pata_ixp4xx_cf.c
+++ b/drivers/ata/pata_ixp4xx_cf.c
@@ -28,10 +28,9 @@
 
 static int ixp4xx_set_mode(struct ata_port *ap, struct ata_device **error)
 {
-        int i;
+        struct ata_device *dev;
 
-        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)) {
                         ata_dev_printk(dev, KERN_INFO, "configured for PIO0\n");
                         dev->pio_mode = XFER_PIO_0;
diff --git a/drivers/ata/pata_legacy.c b/drivers/ata/pata_legacy.c
index 4bcc0ae8d108..9d92843b033d 100644
--- a/drivers/ata/pata_legacy.c
+++ b/drivers/ata/pata_legacy.c
@@ -109,10 +109,9 @@ static int iordy_mask = 0xFFFFFFFF;	/* Use iordy if available */
 
 static int legacy_set_mode(struct ata_port *ap, struct ata_device **unused)
 {
-        int i;
+        struct ata_device *dev;
 
-        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)) {
                         ata_dev_printk(dev, KERN_INFO, "configured for PIO\n");
                         dev->pio_mode = XFER_PIO_0;
diff --git a/drivers/ata/pata_pdc2027x.c b/drivers/ata/pata_pdc2027x.c
index fa780509a1dc..83c90cabc7ff 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);
diff --git a/drivers/ata/pata_platform.c b/drivers/ata/pata_platform.c
index e89656bffa84..ee1605bfc29f 100644
--- a/drivers/ata/pata_platform.c
+++ b/drivers/ata/pata_platform.c
@@ -32,11 +32,9 @@ static int pio_mask = 1;
  */
 static int pata_platform_set_mode(struct ata_port *ap, struct ata_device **unused)
 {
-        int i;
-
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                struct ata_device *dev = &ap->link.device[i];
+        struct ata_device *dev;
 
+        ata_link_for_each_dev(dev, &ap->link) {
                 if (ata_dev_enabled(dev)) {
                         /* We don't really care */
                         dev->pio_mode = dev->xfer_mode = XFER_PIO_0;
diff --git a/drivers/ata/pata_rz1000.c b/drivers/ata/pata_rz1000.c
index 57363c0ce068..300b3d5de81e 100644
--- a/drivers/ata/pata_rz1000.c
+++ b/drivers/ata/pata_rz1000.c
@@ -36,10 +36,9 @@
 
 static int rz1000_set_mode(struct ata_port *ap, struct ata_device **unused)
 {
-        int i;
+        struct ata_device *dev;
 
-        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;
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 */
         }
 
diff --git a/include/linux/libata.h b/include/linux/libata.h
index ca4493125fa0..62fa8cf677a1 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1030,15 +1030,26 @@ static inline unsigned int ata_dev_absent(const struct ata_device *dev)
 }
 
 /*
- * port helpers
+ * link helpers
  */
-static inline int ata_port_max_devices(const struct ata_port *ap)
+static inline int ata_link_max_devices(const struct ata_link *link)
 {
-        if (ap->flags & ATA_FLAG_SLAVE_POSS)
+        if (link->ap->flags & ATA_FLAG_SLAVE_POSS)
                 return 2;
         return 1;
 }
 
+#define ata_port_for_each_link(lk, ap) \
+        for ((lk) = &(ap)->link; (lk); (lk) = NULL)
+
+#define ata_link_for_each_dev(dev, link) \
+        for ((dev) = (link)->device; \
+             (dev) < (link)->device + ata_link_max_devices(link) || ((dev) = NULL); \
+             (dev)++)
+
+#define ata_link_for_each_dev_reverse(dev, link) \
+        for ((dev) = (link)->device + ata_link_max_devices(link) - 1; \
+             (dev) >= (link)->device || ((dev) = NULL); (dev)--)
 
 static inline u8 ata_chk_status(struct ata_port *ap)
 {