SCSI: mpt2sas: Release spinlock for the raid device list before blocking it

BugLink: http://bugs.launchpad.net/bugs/922799

commit 30c43282f3d347f47f9e05199d2b14f56f3f2837 upstream.

Added code to release the spinlock that is used to protect the
raid device list before calling a function that can block. The
blocking was causing a reschedule, and subsequently it is tried
to acquire the same lock, resulting in a panic (NMI Watchdog
detecting a CPU lockup).

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>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
index c79857e439f..2a4719ae688 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
@@ -6425,6 +6425,7 @@ _scsih_mark_responding_raid_device(struct MPT2SAS_ADAPTER *ioc, u64 wwid,
                         } else
                                 sas_target_priv_data = NULL;
                         raid_device->responding = 1;
+                        spin_unlock_irqrestore(&ioc->raid_device_lock, flags);
                         starget_printk(KERN_INFO, raid_device->starget,
                             "handle(0x%04x), wwid(0x%016llx)\n", handle,
                             (unsigned long long)raid_device->wwid);
@@ -6435,16 +6436,16 @@ _scsih_mark_responding_raid_device(struct MPT2SAS_ADAPTER *ioc, u64 wwid,
                          */
                         _scsih_init_warpdrive_properties(ioc, raid_device);
                         if (raid_device->handle == handle)
-                                goto out;
+                                return;
                         printk(KERN_INFO "\thandle changed from(0x%04x)!!!\n",
                             raid_device->handle);
                         raid_device->handle = handle;
                         if (sas_target_priv_data)
                                 sas_target_priv_data->handle = handle;
-                        goto out;
+                        return;
                 }
         }
- out:
+
         spin_unlock_irqrestore(&ioc->raid_device_lock, flags);
 }