mpt2sas: Fix for system hang when discovery in progress

BugLink: http://bugs.launchpad.net/bugs/890952

commit 0167ac67ff6f35bf2364f7672c8012b0cd40277f upstream.

Fix for issue : While discovery is in progress, hot unplug and hot plug of
enclosure connected to the controller card is causing system to hang.

When a device is in the process of being detected at driver load time then
if it is removed, the device that is no longer present will not be added
to the list. So the code in _scsih_probe_sas() is rearranged as such so
the devices that failed to be detected are not added to the list.

Signed-off-by: Nagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
index 8dc2ad4a0a3..5690f09e010 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
@@ -7318,22 +7318,27 @@ _scsih_probe_sas(struct MPT2SAS_ADAPTER *ioc)
         /* SAS Device List */
         list_for_each_entry_safe(sas_device, next, &ioc->sas_device_init_list,
             list) {
-                spin_lock_irqsave(&ioc->sas_device_lock, flags);
-                list_move_tail(&sas_device->list, &ioc->sas_device_list);
-                spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 
                 if (ioc->hide_drives)
                         continue;
 
                 if (!mpt2sas_transport_port_add(ioc, sas_device->handle,
                     sas_device->sas_address_parent)) {
-                        _scsih_sas_device_remove(ioc, sas_device);
+                        list_del(&sas_device->list);
+                        kfree(sas_device);
+                        continue;
                 } else if (!sas_device->starget) {
                         mpt2sas_transport_port_remove(ioc,
                             sas_device->sas_address,
                             sas_device->sas_address_parent);
-                        _scsih_sas_device_remove(ioc, sas_device);
+                        list_del(&sas_device->list);
+                        kfree(sas_device);
+                        continue;
+
                 }
+                spin_lock_irqsave(&ioc->sas_device_lock, flags);
+                list_move_tail(&sas_device->list, &ioc->sas_device_list);
+                spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
         }
 }