scsi: libsas: Do discovery on empty PHY to update PHY info

When we discover the PHY is empty in sas_rediscover_dev(), the PHY
information (like negotiated linkrate) is not updated.

As such, for a user examining sysfs for that PHY, they would see
incorrect values:

root@(none)$ cd /sys/class/sas_phy/phy-0:0:20
root@(none)$ more negotiated_linkrate
3.0 Gbit
root@(none)$ echo 0 > enable
root@(none)$ more negotiated_linkrate
3.0 Gbit

So fix this, simply discover the PHY again, even though we know it's empty;
in the above example, this gives us:

root@(none)$ more negotiated_linkrate
Phy disabled

We must do this after unregistering the device associated with the PHY
(in sas_unregister_devs_sas_addr()).

Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 6f569a65d791..ad96bc843acc 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -2068,6 +2068,11 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
         if ((SAS_ADDR(sas_addr) == 0) || (res == -ECOMM)) {
                 phy->phy_state = PHY_EMPTY;
                 sas_unregister_devs_sas_addr(dev, phy_id, last);
+                /*
+                 * Even though the PHY is empty, for convenience we discover
+                 * the PHY to update the PHY info, like negotiated linkrate.
+                 */
+                sas_ex_phy_discover(dev, phy_id);
                 return res;
         } else if (SAS_ADDR(sas_addr) == SAS_ADDR(phy->attached_sas_addr) &&
                    dev_type_flutter(type, phy->attached_dev_type)) {