[Xen-changelog] Detect failure to create shutdown process and retry twice

[Xen patchbot -unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 938f209d886be754eaeff4683b021bb4647078a1
# Parent  4c9dbbb5fe3dae45a3016acc65b032e606dca270
Detect failure to create shutdown process and retry twice
per second until it succeeds.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>

diff -r 4c9dbbb5fe3d -r 938f209d886b 
linux-2.6-xen-sparse/arch/xen/kernel/reboot.c
--- a/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c     Sat Oct 15 11:56:07 2005
+++ b/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c     Sat Oct 15 15:25:05 2005
@@ -26,7 +26,6 @@
 // the distinction when we return the reason code to them.
 #define SHUTDOWN_HALT      4
 
-
 void machine_restart(char * __unused)
 {
        /* We really want to get pending console data out before we die. */
@@ -60,6 +59,8 @@
 
 /* Ignore multiple shutdown requests. */
 static int shutting_down = SHUTDOWN_INVALID;
+static void __shutdown_handler(void *unused);
+static DECLARE_WORK(shutdown_work, __shutdown_handler, NULL);
 
 #ifndef CONFIG_HOTPLUG_CPU
 #define cpu_down(x) (-EOPNOTSUPP)
@@ -243,40 +244,46 @@
        return 0;
 }
 
-static struct task_struct *kthread_create_on_cpu(int (*f)(void *arg),
-                                                void *arg,
-                                                const char *name,
-                                                int cpu)
+static int kthread_create_on_cpu(int (*f)(void *arg),
+                                void *arg,
+                                const char *name,
+                                int cpu)
 {
        struct task_struct *p;
        p = kthread_create(f, arg, name);
+       if (IS_ERR(p))
+               return PTR_ERR(p);
        kthread_bind(p, cpu);
        wake_up_process(p);
-       return p;
+       return 0;
 }
 
 static void __shutdown_handler(void *unused)
 {
        int err;
 
-       if (shutting_down != SHUTDOWN_SUSPEND) {
+       if (shutting_down != SHUTDOWN_SUSPEND)
                err = kernel_thread(shutdown_process, NULL,
                                    CLONE_FS | CLONE_FILES);
-               if ( err < 0 )
-                       printk(KERN_ALERT "Error creating shutdown "
-                              "process!\n");
-       } else {
-               kthread_create_on_cpu(__do_suspend, NULL, "suspender", 0);
+       else
+               err = kthread_create_on_cpu(__do_suspend, NULL, "suspend", 0);
+
+       if ( err < 0 ) {
+               printk(KERN_WARNING "Error creating shutdown process (%d): "
+                      "retrying...\n", -err);
+               schedule_delayed_work(&shutdown_work, HZ/2);
        }
 }
 
 static void shutdown_handler(struct xenbus_watch *watch,
                             const char **vec, unsigned int len)
 {
-       static DECLARE_WORK(shutdown_work, __shutdown_handler, NULL);
        char *str;
        struct xenbus_transaction *xbt;
        int err;
+
+       if (shutting_down != SHUTDOWN_INVALID)
+               goto out;
 
  again:
        xbt = xenbus_transaction_start();
@@ -312,6 +319,7 @@
 
        kfree(str);
 
+ out:
        if (shutting_down != SHUTDOWN_INVALID)
                schedule_work(&shutdown_work);
 }

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