[IA64] kdump: Short path to freeze CPUs

Setting monarch_cpu = -1 to let slaves frozen might not work, because
there might be slaves being late, not entered the rendezvous yet.
Such slaves might be caught in while (monarch_cpu == -1) loop.

Use kdump_in_progress instead of monarch_cpus to break INIT rendezvous
and let all slaves enter DIE_INIT_SLAVE_LEAVE smoothly.

And monarch no longer need to manage rendezvous if once kdump_in_progress
is set, catch the monarch in DIE_INIT_MONARCH_ENTER then.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: kexec@lists.infradead.org
Acked-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 7b30d21c5190..d2877a7bfe2e 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -1682,14 +1682,25 @@ ia64_init_handler(struct pt_regs *regs, struct switch_stack *sw,
 
         if (!sos->monarch) {
                 ia64_mc_info.imi_rendez_checkin[cpu] = IA64_MCA_RENDEZ_CHECKIN_INIT;
+
+#ifdef CONFIG_KEXEC
+                while (monarch_cpu == -1 && !atomic_read(&kdump_in_progress))
+                        udelay(1000);
+#else
                 while (monarch_cpu == -1)
-                       cpu_relax();     /* spin until monarch enters */
+                        cpu_relax();    /* spin until monarch enters */
+#endif
 
                 NOTIFY_INIT(DIE_INIT_SLAVE_ENTER, regs, (long)&nd, 1);
                 NOTIFY_INIT(DIE_INIT_SLAVE_PROCESS, regs, (long)&nd, 1);
 
+#ifdef CONFIG_KEXEC
+                while (monarch_cpu != -1 && !atomic_read(&kdump_in_progress))
+                        udelay(1000);
+#else
                 while (monarch_cpu != -1)
-                       cpu_relax();     /* spin until monarch leaves */
+                        cpu_relax();    /* spin until monarch leaves */
+#endif
 
                 NOTIFY_INIT(DIE_INIT_SLAVE_LEAVE, regs, (long)&nd, 1);