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, 4 insertions, 2 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 63c743baf920..5f7d5f9ee820 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5636,6 +5636,7 @@ struct ata_port *ata_port_alloc(struct ata_host *host)
         ap->pflags |= ATA_PFLAG_INITIALIZING | ATA_PFLAG_FROZEN;
         ap->lock = &host->lock;
         ap->print_id = -1;
+        ap->local_port_no = -1;
         ap->host = host;
         ap->dev = host->dev;
 
@@ -6126,9 +6127,10 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
                 kfree(host->ports[i]);
 
         /* give ports names and add SCSI hosts */
-        for (i = 0; i < host->n_ports; i++)
+        for (i = 0; i < host->n_ports; i++) {
                 host->ports[i]->print_id = atomic_inc_return(&ata_print_id);
-
+                host->ports[i]->local_port_no = i + 1;
+        }
 
         /* Create associated sysfs transport objects  */
         for (i = 0; i < host->n_ports; i++) {