[SCSI] libsas: fix sas_get_port_device regression

Commit 899fcf4 "[SCSI] libsas: set attached device type and target
protocols for local phys" setup 'phy' to be dereferenced after
list_for_each_entry(phy, &port->phy_list, port_phy_el) (i.e. phy ==
&port->phy_list) resulting in reports like:

  BUG: unable to handle kernel NULL pointer dereference at 00000000000002b0
  IP: [<ffffffffa00ce948>] sas_discover_domain+0x29e/0x4fb [libsas]

...fix by deferring sas_phy_set_target() to the end of
sas_get_port_device().

Reported-by: Tom Jackson <thomas.p.jackson@intel.com>
Tested-by: Tom Jackson <thomas.p.jackson@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index c7ac88288bf1..658f16cc2f03 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -134,10 +134,6 @@ static int sas_get_port_device(struct asd_sas_port *port)
                 return -ENODEV;
         }
 
-        spin_lock_irq(&port->phy_list_lock);
-        list_for_each_entry(phy, &port->phy_list, port_phy_el)
-                sas_phy_set_target(phy, dev);
-        spin_unlock_irq(&port->phy_list_lock);
         rphy->identify.phy_identifier = phy->phy->identify.phy_identifier;
         memcpy(dev->sas_addr, port->attached_sas_addr, SAS_ADDR_SIZE);
         sas_fill_in_rphy(dev, rphy);
@@ -164,6 +160,11 @@ static int sas_get_port_device(struct asd_sas_port *port)
                 spin_unlock_irq(&port->dev_list_lock);
         }
 
+        spin_lock_irq(&port->phy_list_lock);
+        list_for_each_entry(phy, &port->phy_list, port_phy_el)
+                sas_phy_set_target(phy, dev);
+        spin_unlock_irq(&port->phy_list_lock);
+
         return 0;
 }