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Subject[PATCH 4.4 137/241] scsi: libsas: Do discovery on empty PHY to update PHY info
Date
[ Upstream commit d8649fc1c5e40e691d589ed825998c36a947491c ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/libsas/sas_expander.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 1a6f65db615e8..ee1f9ee995e53 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -2027,6 +2027,11 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id, bool last)
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)) {
--
2.20.1


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