src/patches/suse-2.6.27.25/patches.arch/s390-08-03-iucv-cpu-hotremove.diff

   1 From: Gerald Schaefer <geraldsc@de.ibm.com>
   2 Subject: iucv: failing cpu hot remove for inactive iucv
   3 References: bnc#466462,LTC#51104
   4
   5 Symptom:     cpu hot remove rejected with NOTIFY_BAD
   6 Problem:     If the iucv module is compiled in / loaded but no user
   7              is registered, cpu hot remove doesn't work. The iucv
   8              cpu hotplug notifier on CPU_DOWN_PREPARE checks, if
   9              the iucv_buffer_cpumask would be empty after the
  10              corresponding bit would be cleared. However the bit
  11              was never set since iucv wasn't enabled. That causes
  12              all cpu hot unplug operations to fail in this scenario.
  13 Solution:    Use iucv_path_table as an indicator whether iucv is
  14              enabled or not.
  15
  16 Acked-by: John Jolly <jjolly@suse.de>
  17 ---
  18
  19  net/iucv/iucv.c |   18 +++++++++++-------
  20  1 file changed, 11 insertions(+), 7 deletions(-)
  21
  22 Index: linux-sles11/net/iucv/iucv.c
  23 ===================================================================
  24 --- linux-sles11.orig/net/iucv/iucv.c
  25 +++ linux-sles11/net/iucv/iucv.c
  26 @@ -516,6 +516,7 @@ static int iucv_enable(void)
  27         size_t alloc_size;
  28         int cpu, rc;
  29
  30 +       get_online_cpus();
  31         rc = -ENOMEM;
  32         alloc_size = iucv_max_pathid * sizeof(struct iucv_path);
  33         iucv_path_table = kzalloc(alloc_size, GFP_KERNEL);
  34 @@ -523,19 +524,17 @@ static int iucv_enable(void)
  35                 goto out;
  36         /* Declare per cpu buffers. */
  37         rc = -EIO;
  38 -       get_online_cpus();
  39         for_each_online_cpu(cpu)
  40                 smp_call_function_single(cpu, iucv_declare_cpu, NULL, 1);
  41         if (cpus_empty(iucv_buffer_cpumask))
  42                 /* No cpu could declare an iucv buffer. */
  43 -               goto out_path;
  44 +               goto out;
  45         put_online_cpus();
  46         return 0;
  47 -
  48 -out_path:
  49 -       put_online_cpus();
  50 -       kfree(iucv_path_table);
  51  out:
  52 +       kfree(iucv_path_table);
  53 +       iucv_path_table = NULL;
  54 +       put_online_cpus();
  55         return rc;
  56  }
  57
  58 @@ -550,8 +549,9 @@ static void iucv_disable(void)
  59  {
  60         get_online_cpus();
  61         on_each_cpu(iucv_retrieve_cpu, NULL, 1);
  62 -       put_online_cpus();
  63         kfree(iucv_path_table);
  64 +       iucv_path_table = NULL;
  65 +       put_online_cpus();
  66  }
  67
  68  static int __cpuinit iucv_cpu_notify(struct notifier_block *self,
  69 @@ -588,10 +588,14 @@ static int __cpuinit iucv_cpu_notify(str
  70         case CPU_ONLINE_FROZEN:
  71         case CPU_DOWN_FAILED:
  72         case CPU_DOWN_FAILED_FROZEN:
  73 +               if (!iucv_path_table)
  74 +                       break;
  75                 smp_call_function_single(cpu, iucv_declare_cpu, NULL, 1);
  76                 break;
  77         case CPU_DOWN_PREPARE:
  78         case CPU_DOWN_PREPARE_FROZEN:
  79 +               if (!iucv_path_table)
  80 +                       break;
  81                 cpumask = iucv_buffer_cpumask;
  82                 cpu_clear(cpu, cpumask);
  83                 if (cpus_empty(cpumask))