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, 59 insertions, 58 deletions

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);