libata: beef up iterators

There currently are the following looping constructs.

* __ata_port_for_each_link() for all available links
* ata_port_for_each_link() for edge links
* ata_link_for_each_dev() for all devices
* ata_link_for_each_dev_reverse() for all devices in reverse order

Now there's a need for looping construct which is similar to
__ata_port_for_each_link() but iterates over PMP links before the host
link.  Instead of adding another one with long name, do the following
cleanup.

* Implement and export ata_link_next() and ata_dev_next() which take
  @mode parameter and can be used to build custom loop.
* Implement ata_for_each_link() and ata_for_each_dev() which take
  looping mode explicitly.

The following iteration modes are implemented.

* ATA_LITER_EDGE		: loop over edge links
* ATA_LITER_HOST_FIRST		: loop over all links, host link first
* ATA_LITER_PMP_FIRST		: loop over all links, PMP links first

* ATA_DITER_ENABLED		: loop over enabled devices
* ATA_DITER_ENABLED_REVERSE	: loop over enabled devices in reverse order
* ATA_DITER_ALL			: loop over all devices
* ATA_DITER_ALL_REVERSE		: loop over all devices in reverse order

This change removes exlicit device enabledness checks from many loops
and makes it clear which ones are iterated over in which direction.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index a67b8e7..656448c 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1119,14 +1119,14 @@ static void ahci_start_port(struct ata_port *ap)
 
 	/* turn on LEDs */
 	if (ap->flags & ATA_FLAG_EM) {
-		ata_port_for_each_link(link, ap) {
+		ata_for_each_link(link, ap, EDGE) {
 			emp = &pp->em_priv[link->pmp];
 			ahci_transmit_led_message(ap, emp->led_state, 4);
 		}
 	}
 
 	if (ap->flags & ATA_FLAG_SW_ACTIVITY)
-		ata_port_for_each_link(link, ap)
+		ata_for_each_link(link, ap, EDGE)
 			ahci_init_sw_activity(link);
 
 }
@@ -1361,7 +1361,7 @@ static ssize_t ahci_led_show(struct ata_port *ap, char *buf)
 	struct ahci_em_priv *emp;
 	int rc = 0;
 
-	ata_port_for_each_link(link, ap) {
+	ata_for_each_link(link, ap, EDGE) {
 		emp = &pp->em_priv[link->pmp];
 		rc += sprintf(buf, "%lx\n", emp->led_state);
 	}
@@ -1941,7 +1941,7 @@ static void ahci_error_intr(struct ata_port *ap, u32 irq_stat)
 	u32 serror;
 
 	/* determine active link */
-	ata_port_for_each_link(link, ap)
+	ata_for_each_link(link, ap, EDGE)
 		if (ata_link_active(link))
 			break;
 	if (!link)