libata: reimplement link iterator

Implement __ata_port_next_link() and reimplement
__ata_port_for_each_link() and ata_port_for_each_link() using it.
This removes relatively large inlined code and makes iteration easier
to extend.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-core.c

@@ -163,6 +163,35 @@ MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_VERSION);
 
 
+/*
+ * Iterator helpers.  Don't use directly.
+ *
+ * LOCKING:
+ * Host lock or EH context.
+ */
+struct ata_link *__ata_port_next_link(struct ata_port *ap,
+				      struct ata_link *link, bool dev_only)
+{
+	/* NULL link indicates start of iteration */
+	if (!link) {
+		if (dev_only && sata_pmp_attached(ap))
+			return ap->pmp_link;
+		return &ap->link;
+	}
+
+	/* we just iterated over the host link, what's next? */
+	if (ata_is_host_link(link)) {
+		if (!sata_pmp_attached(ap))
+			return NULL;
+		return ap->pmp_link;
+	}
+
+	/* iterate to the next PMP link */
+	if (++link < ap->pmp_link + ap->nr_pmp_links)
+		return link;
+	return NULL;
+}
+
 /**
  *	ata_force_cbl - force cable type according to libata.force
  *	@ap: ATA port of interest
@@ -6255,6 +6284,7 @@ EXPORT_SYMBOL_GPL(ata_base_port_ops);
 EXPORT_SYMBOL_GPL(sata_port_ops);
 EXPORT_SYMBOL_GPL(ata_dummy_port_ops);
 EXPORT_SYMBOL_GPL(ata_dummy_port_info);
+EXPORT_SYMBOL_GPL(__ata_port_next_link);
 EXPORT_SYMBOL_GPL(ata_std_bios_param);
 EXPORT_SYMBOL_GPL(ata_host_init);
 EXPORT_SYMBOL_GPL(ata_host_alloc);

include/linux/libata.h

@@ -1265,34 +1265,17 @@ static inline int ata_link_active(struct ata_link *link)
 	return ata_tag_valid(link->active_tag) || link->sactive;
 }
 
-static inline struct ata_link *ata_port_first_link(struct ata_port *ap)
-{
-	if (sata_pmp_attached(ap))
-		return ap->pmp_link;
-	return &ap->link;
-}
-
-static inline struct ata_link *ata_port_next_link(struct ata_link *link)
-{
-	struct ata_port *ap = link->ap;
-
-	if (ata_is_host_link(link)) {
-		if (!sata_pmp_attached(ap))
-			return NULL;
-		return ap->pmp_link;
-	}
-
-	if (++link < ap->nr_pmp_links + ap->pmp_link)
-		return link;
-	return NULL;
-}
+extern struct ata_link *__ata_port_next_link(struct ata_port *ap,
+					     struct ata_link *link,
+					     bool dev_only);
 
-#define __ata_port_for_each_link(lk, ap) \
-	for ((lk) = &(ap)->link; (lk); (lk) = ata_port_next_link(lk))
+#define __ata_port_for_each_link(link, ap) \
+	for ((link) = __ata_port_next_link((ap), NULL, false); (link); \
+	     (link) = __ata_port_next_link((ap), (link), false))
 
 #define ata_port_for_each_link(link, ap) \
-	for ((link) = ata_port_first_link(ap); (link); \
-	     (link) = ata_port_next_link(link))
+	for ((link) = __ata_port_next_link((ap), NULL, true); (link); \
+	     (link) = __ata_port_next_link((ap), (link), true))
 
 #define ata_link_for_each_dev(dev, link) \
 	for ((dev) = (link)->device; \