SCSI: libsas: fix sas_discover_devices return code handling

commit b17caa174a7e1fd2e17b26e210d4ee91c4c28b37 upstream.

commit 198439e4 [SCSI] libsas: do not set res = 0 in sas_ex_discover_dev()
commit 19252de6 [SCSI] libsas: fix wide port hotplug issues

The above commits seem to have confused the return value of
sas_ex_discover_dev which is non-zero on failure and
sas_ex_join_wide_port which just indicates short circuiting discovery on
already established ports.  The result is random discovery failures
depending on configuration.

Calls to sas_ex_join_wide_port are the source of the trouble as its
return value is errantly assigned to 'res'.  Convert it to bool and stop
returning its result up the stack.

Tested-by: Dan Melnic <dan.melnic@amd.com>
Reported-by: Dan Melnic <dan.melnic@amd.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 12 insertions, 27 deletions

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index e8ebe688326..d2f95761ba3 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -770,7 +770,7 @@ static struct domain_device *sas_ex_discover_end_dev(
 }
 
 /* See if this phy is part of a wide port */
-static int sas_ex_join_wide_port(struct domain_device *parent, int phy_id)
+static bool sas_ex_join_wide_port(struct domain_device *parent, int phy_id)
 {
         struct ex_phy *phy = &parent->ex_dev.ex_phy[phy_id];
         int i;
@@ -786,11 +786,11 @@ static int sas_ex_join_wide_port(struct domain_device *parent, int phy_id)
                         sas_port_add_phy(ephy->port, phy->phy);
                         phy->port = ephy->port;
                         phy->phy_state = PHY_DEVICE_DISCOVERED;
-                        return 0;
+                        return true;
                 }
         }
 
-        return -ENODEV;
+        return false;
 }
 
 static struct domain_device *sas_ex_discover_expander(
@@ -928,8 +928,7 @@ static int sas_ex_discover_dev(struct domain_device *dev, int phy_id)
                 return res;
         }
 
-        res = sas_ex_join_wide_port(dev, phy_id);
-        if (!res) {
+        if (sas_ex_join_wide_port(dev, phy_id)) {
                 SAS_DPRINTK("Attaching ex phy%d to wide port %016llx\n",
                             phy_id, SAS_ADDR(ex_phy->attached_sas_addr));
                 return res;
@@ -974,8 +973,7 @@ static int sas_ex_discover_dev(struct domain_device *dev, int phy_id)
                         if (SAS_ADDR(ex->ex_phy[i].attached_sas_addr) ==
                             SAS_ADDR(child->sas_addr)) {
                                 ex->ex_phy[i].phy_state= PHY_DEVICE_DISCOVERED;
-                                res = sas_ex_join_wide_port(dev, i);
-                                if (!res)
+                                if (sas_ex_join_wide_port(dev, i))
                                         SAS_DPRINTK("Attaching ex phy%d to wide port %016llx\n",
                                                     i, SAS_ADDR(ex->ex_phy[i].attached_sas_addr));
 
@@ -1838,32 +1836,20 @@ static int sas_discover_new(struct domain_device *dev, int phy_id)
 {
         struct ex_phy *ex_phy = &dev->ex_dev.ex_phy[phy_id];
         struct domain_device *child;
-        bool found = false;
-        int res, i;
+        int res;
 
         SAS_DPRINTK("ex %016llx phy%d new device attached\n",
                     SAS_ADDR(dev->sas_addr), phy_id);
         res = sas_ex_phy_discover(dev, phy_id);
         if (res)
-                goto out;
-        /* to support the wide port inserted */
-        for (i = 0; i < dev->ex_dev.num_phys; i++) {
-                struct ex_phy *ex_phy_temp = &dev->ex_dev.ex_phy[i];
-                if (i == phy_id)
-                        continue;
-                if (SAS_ADDR(ex_phy_temp->attached_sas_addr) ==
-                    SAS_ADDR(ex_phy->attached_sas_addr)) {
-                        found = true;
-                        break;
-                }
-        }
-        if (found) {
-                sas_ex_join_wide_port(dev, phy_id);
+                return res;
+
+        if (sas_ex_join_wide_port(dev, phy_id))
                 return 0;
-        }
+
         res = sas_ex_discover_devices(dev, phy_id);
-        if (!res)
-                goto out;
+        if (res)
+                return res;
         list_for_each_entry(child, &dev->ex_dev.children, siblings) {
                 if (SAS_ADDR(child->sas_addr) ==
                     SAS_ADDR(ex_phy->attached_sas_addr)) {
@@ -1873,7 +1859,6 @@ static int sas_discover_new(struct domain_device *dev, int phy_id)
                         break;
                 }
         }
-out:
         return res;
 }