releases/3.1.10/scsi-mpt2sas-release-spinlock-for-the-raid-device-list-before-blocking-it.patch

   1 From 30c43282f3d347f47f9e05199d2b14f56f3f2837 Mon Sep 17 00:00:00 2001
   2 From: "nagalakshmi.nandigama@lsi.com" <nagalakshmi.nandigama@lsi.com>
   3 Date: Thu, 1 Dec 2011 07:52:56 +0530
   4 Subject: SCSI: mpt2sas: Release spinlock for the raid device list before blocking it
   5
   6 From: "nagalakshmi.nandigama@lsi.com" <nagalakshmi.nandigama@lsi.com>
   7
   8 commit 30c43282f3d347f47f9e05199d2b14f56f3f2837 upstream.
   9
  10 Added code to release the spinlock that is used to protect the
  11 raid device list before calling a function that can block. The
  12 blocking was causing a reschedule, and subsequently it is tried
  13 to acquire the same lock, resulting in a panic (NMI Watchdog
  14 detecting a CPU lockup).
  15
  16 Signed-off-by: Nagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>
  17 Signed-off-by: James Bottomley <JBottomley@Parallels.com>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  19
  20 ---
  21  drivers/scsi/mpt2sas/mpt2sas_scsih.c |    7 ++++---
  22  1 file changed, 4 insertions(+), 3 deletions(-)
  23
  24 --- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
  25 +++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
  26 @@ -6564,6 +6564,7 @@ _scsih_mark_responding_raid_device(struc
  27                         } else
  28                                 sas_target_priv_data = NULL;
  29                         raid_device->responding = 1;
  30 +                       spin_unlock_irqrestore(&ioc->raid_device_lock, flags);
  31                         starget_printk(KERN_INFO, raid_device->starget,
  32                             "handle(0x%04x), wwid(0x%016llx)\n", handle,
  33                             (unsigned long long)raid_device->wwid);
  34 @@ -6574,16 +6575,16 @@ _scsih_mark_responding_raid_device(struc
  35                          */
  36                         _scsih_init_warpdrive_properties(ioc, raid_device);
  37                         if (raid_device->handle == handle)
  38 -                               goto out;
  39 +                               return;
  40                         printk(KERN_INFO "\thandle changed from(0x%04x)!!!\n",
  41                             raid_device->handle);
  42                         raid_device->handle = handle;
  43                         if (sas_target_priv_data)
  44                                 sas_target_priv_data->handle = handle;
  45 -                       goto out;
  46 +                       return;
  47                 }
  48         }
  49 - out:
  50 +
  51         spin_unlock_irqrestore(&ioc->raid_device_lock, flags);
  52  }
  53