libata: export ata_port port_no attribute via /sys

While registering host controller track port number based upon number
of ports available on the controller, export port_no attribute through
/sys. This patch is needed by udev for composing persistent links in
/dev/disk/by-path.

/sys/devices/pci0000:00/0000:00:1f.2/ata8/ata_port/ata8
total 0
lrwxrwxrwx. 1 root root    0 Mar  6 12:43 device -> ../../../ata8
-r--r--r--. 1 root root 4096 Mar  6 12:43 idle_irq
-r--r--r--. 1 root root 4096 Mar  6 12:43 nr_pmp_links
-r--r--r--. 1 root root 4096 Mar  6 12:43 port_no
drwxr-xr-x. 2 root root    0 Mar  6 12:42 power
lrwxrwxrwx. 1 root root    0 Mar  6 12:41 subsystem -> ../../../../../../class/ata_port
-rw-r--r--. 1 root root 4096 Mar  6 12:40 uevent
1

Signed-off-by: David Milburn <dmilburn@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transport.c
index c04d393d20c1..077a856f5fd0 100644
--- a/drivers/ata/libata-transport.c
+++ b/drivers/ata/libata-transport.c
@@ -37,7 +37,7 @@
 #include "libata.h"
 #include "libata-transport.h"
 
-#define ATA_PORT_ATTRS		2
+#define ATA_PORT_ATTRS		3
 #define ATA_LINK_ATTRS		3
 #define ATA_DEV_ATTRS		9
 
@@ -216,6 +216,7 @@ static DEVICE_ATTR(name, S_IRUGO, show_ata_port_##name, NULL)
 
 ata_port_simple_attr(nr_pmp_links, nr_pmp_links, "%d\n", int);
 ata_port_simple_attr(stats.idle_irq, idle_irq, "%ld\n", unsigned long);
+ata_port_simple_attr(local_port_no, port_no, "%u\n", unsigned int);
 
 static DECLARE_TRANSPORT_CLASS(ata_port_class,
 			       "ata_port", NULL, NULL, NULL);
@@ -709,6 +710,7 @@ struct scsi_transport_template *ata_attach_transport(void)
 	count = 0;
 	SETUP_PORT_ATTRIBUTE(nr_pmp_links);
 	SETUP_PORT_ATTRIBUTE(idle_irq);
+	SETUP_PORT_ATTRIBUTE(port_no);
 	BUG_ON(count > ATA_PORT_ATTRS);
 	i->port_attrs[count] = NULL;