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>

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 825461a33abe..d156616f45f5 100644
--- a/drivers/ata/libata-core.c
+++ b/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);