xen/manage: fix potential deadlock when resuming the console

[cascardo/linux.git] / drivers / xen / manage.c

diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index fc6c94c..5f1e1f3 100644 (file)
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -41,9 +41,6 @@ static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
 
 struct suspend_info {
        int cancelled;
-       unsigned long arg; /* extra hypercall argument */
-       void (*pre)(void);
-       void (*post)(int cancelled);
 };
 
 static RAW_NOTIFIER_HEAD(xen_resume_notifier);
@@ -61,26 +58,6 @@ void xen_resume_notifier_unregister(struct notifier_block *nb)
 EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
 
 #ifdef CONFIG_HIBERNATE_CALLBACKS
-static void xen_hvm_post_suspend(int cancelled)
-{
-       xen_arch_hvm_post_suspend(cancelled);
-       gnttab_resume();
-}
-
-static void xen_pre_suspend(void)
-{
-       xen_mm_pin_all();
-       gnttab_suspend();
-       xen_arch_pre_suspend();
-}
-
-static void xen_post_suspend(int cancelled)
-{
-       xen_arch_post_suspend(cancelled);
-       gnttab_resume();
-       xen_mm_unpin_all();
-}
-
 static int xen_suspend(void *data)
 {
        struct suspend_info *si = data;
@@ -94,22 +71,23 @@ static int xen_suspend(void *data)
                return err;
        }
 
-       if (si->pre)
-               si->pre();
+       gnttab_suspend();
+       xen_arch_pre_suspend();
 
        /*
         * This hypercall returns 1 if suspend was cancelled
         * or the domain was merely checkpointed, and 0 if it
         * is resuming in a new domain.
         */
-       si->cancelled = HYPERVISOR_suspend(si->arg);
+       si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
+                                           ? virt_to_mfn(xen_start_info)
+                                           : 0);
 
-       if (si->post)
-               si->post(si->cancelled);
+       xen_arch_post_suspend(si->cancelled);
+       gnttab_resume();
 
        if (!si->cancelled) {
                xen_irq_resume();
-               xen_console_resume();
                xen_timer_resume();
        }
 
@@ -154,18 +132,12 @@ static void do_suspend(void)
 
        si.cancelled = 1;
 
-       if (xen_hvm_domain()) {
-               si.arg = 0UL;
-               si.pre = NULL;
-               si.post = &xen_hvm_post_suspend;
-       } else {
-               si.arg = virt_to_mfn(xen_start_info);
-               si.pre = &xen_pre_suspend;
-               si.post = &xen_post_suspend;
-       }
-
        err = stop_machine(xen_suspend, &si, cpumask_of(0));
 
+       /* Resume console as early as possible. */
+       if (!si.cancelled)
+               xen_console_resume();
+
        raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
 
        dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
@@ -198,10 +170,32 @@ struct shutdown_handler {
        void (*cb)(void);
 };
 
+static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
+{
+       switch (code) {
+       case SYS_DOWN:
+       case SYS_HALT:
+       case SYS_POWER_OFF:
+               shutting_down = SHUTDOWN_POWEROFF;
+       default:
+               break;
+       }
+       return NOTIFY_DONE;
+}
 static void do_poweroff(void)
 {
-       shutting_down = SHUTDOWN_POWEROFF;
-       orderly_poweroff(false);
+       switch (system_state) {
+       case SYSTEM_BOOTING:
+               orderly_poweroff(true);
+               break;
+       case SYSTEM_RUNNING:
+               orderly_poweroff(false);
+               break;
+       default:
+               /* Don't do it when we are halting/rebooting. */
+               pr_info("Ignoring Xen toolstack shutdown.\n");
+               break;
+       }
 }
 
 static void do_reboot(void)
@@ -307,6 +301,10 @@ static struct xenbus_watch shutdown_watch = {
        .callback = shutdown_handler
 };
 
+static struct notifier_block xen_reboot_nb = {
+       .notifier_call = poweroff_nb,
+};
+
 static int setup_shutdown_watcher(void)
 {
        int err;
@@ -317,6 +315,7 @@ static int setup_shutdown_watcher(void)
                return err;
        }
 
+
 #ifdef CONFIG_MAGIC_SYSRQ
        err = register_xenbus_watch(&sysrq_watch);
        if (err) {
@@ -345,6 +344,7 @@ int xen_setup_shutdown_event(void)
        if (!xen_domain())
                return -ENODEV;
        register_xenstore_notifier(&xenstore_notifier);
+       register_reboot_notifier(&xen_reboot_nb);
 
        return 0;
 }