Merge branch 'sched/urgent' into sched/core, to avoid conflicts

Signed-off-by: Ingo Molnar <mingo@kernel.org>

13 files changed, 176 insertions, 165 deletions

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 61a6ac8fa8fc..b7a506f2bb14 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -604,19 +604,29 @@ static void __init balloon_add_region(unsigned long start_pfn,
 	}
 }
 
+static int alloc_balloon_scratch_page(int cpu)
+{
+	if (per_cpu(balloon_scratch_page, cpu) != NULL)
+		return 0;
+
+	per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL);
+	if (per_cpu(balloon_scratch_page, cpu) == NULL) {
+		pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+
 static int balloon_cpu_notify(struct notifier_block *self,
 				    unsigned long action, void *hcpu)
 {
 	int cpu = (long)hcpu;
 	switch (action) {
 	case CPU_UP_PREPARE:
-		if (per_cpu(balloon_scratch_page, cpu) != NULL)
-			break;
-		per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL);
-		if (per_cpu(balloon_scratch_page, cpu) == NULL) {
-			pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu);
+		if (alloc_balloon_scratch_page(cpu))
 			return NOTIFY_BAD;
-		}
 		break;
 	default:
 		break;
@@ -636,15 +646,17 @@ static int __init balloon_init(void)
 		return -ENODEV;
 
 	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
-		for_each_online_cpu(cpu)
-		{
-			per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL);
-			if (per_cpu(balloon_scratch_page, cpu) == NULL) {
-				pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu);
+		register_cpu_notifier(&balloon_cpu_notifier);
+
+		get_online_cpus();
+		for_each_online_cpu(cpu) {
+			if (alloc_balloon_scratch_page(cpu)) {
+				put_online_cpus();
+				unregister_cpu_notifier(&balloon_cpu_notifier);
 				return -ENOMEM;
 			}
 		}
-		register_cpu_notifier(&balloon_cpu_notifier);
+		put_online_cpus();
 	}
 
 	pr_info("Initialising balloon driver\n");
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index c3458f58de90..dfa12a4a0a48 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -388,10 +388,10 @@ static void xen_irq_init(unsigned irq)
 	list_add_tail(&info->list, &xen_irq_list_head);
 }
 
-static int __must_check xen_allocate_irq_dynamic(void)
+static int __must_check xen_allocate_irqs_dynamic(int nvec)
 {
 	int first = 0;
-	int irq;
+	int i, irq;
 
 #ifdef CONFIG_X86_IO_APIC
 	/*
@@ -405,14 +405,22 @@ static int __must_check xen_allocate_irq_dynamic(void)
 		first = get_nr_irqs_gsi();
 #endif
 
-	irq = irq_alloc_desc_from(first, -1);
+	irq = irq_alloc_descs_from(first, nvec, -1);
 
-	if (irq >= 0)
-		xen_irq_init(irq);
+	if (irq >= 0) {
+		for (i = 0; i < nvec; i++)
+			xen_irq_init(irq + i);
+	}
 
 	return irq;
 }
 
+static inline int __must_check xen_allocate_irq_dynamic(void)
+{
+
+	return xen_allocate_irqs_dynamic(1);
+}
+
 static int __must_check xen_allocate_irq_gsi(unsigned gsi)
 {
 	int irq;
@@ -466,9 +474,6 @@ static void xen_evtchn_close(unsigned int port)
 	close.port = port;
 	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 		BUG();
-
-	/* Closed ports are implicitly re-bound to VCPU0. */
-	bind_evtchn_to_cpu(port, 0);
 }
 
 static void pirq_query_unmask(int irq)
@@ -730,22 +735,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
 }
 
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
-			     int pirq, const char *name, domid_t domid)
+			     int pirq, int nvec, const char *name, domid_t domid)
 {
-	int irq, ret;
+	int i, irq, ret;
 
 	mutex_lock(&irq_mapping_update_lock);
 
-	irq = xen_allocate_irq_dynamic();
+	irq = xen_allocate_irqs_dynamic(nvec);
 	if (irq < 0)
 		goto out;
 
-	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
-			name);
+	for (i = 0; i < nvec; i++) {
+		irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
+
+		ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
+					      i == 0 ? 0 : PIRQ_MSI_GROUP);
+		if (ret < 0)
+			goto error_irq;
+	}
 
-	ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
-	if (ret < 0)
-		goto error_irq;
 	ret = irq_set_msi_desc(irq, msidesc);
 	if (ret < 0)
 		goto error_irq;
@@ -753,7 +761,8 @@ out:
 	mutex_unlock(&irq_mapping_update_lock);
 	return irq;
 error_irq:
-	__unbind_from_irq(irq);
+	for (; i >= 0; i--)
+		__unbind_from_irq(irq + i);
 	mutex_unlock(&irq_mapping_update_lock);
 	return ret;
 }
@@ -767,7 +776,12 @@ int xen_destroy_irq(int irq)
 
 	mutex_lock(&irq_mapping_update_lock);
 
-	if (xen_initial_domain()) {
+	/*
+	 * If trying to remove a vector in a MSI group different
+	 * than the first one skip the PIRQ unmap unless this vector
+	 * is the first one in the group.
+	 */
+	if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
 		unmap_irq.pirq = info->u.pirq.pirq;
 		unmap_irq.domid = info->u.pirq.domid;
 		rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
@@ -1234,8 +1248,8 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 	irq_enter();
 #ifdef CONFIG_X86
 	exit_idle();
-#endif
 	inc_irq_stat(irq_hv_callback_count);
+#endif
 
 	__xen_evtchn_do_upcall();
 
@@ -1329,26 +1343,6 @@ static int set_affinity_irq(struct irq_data *data, const struct cpumask *dest,
 	return rebind_irq_to_cpu(data->irq, tcpu);
 }
 
-static int retrigger_evtchn(int evtchn)
-{
-	int masked;
-
-	if (!VALID_EVTCHN(evtchn))
-		return 0;
-
-	masked = test_and_set_mask(evtchn);
-	set_evtchn(evtchn);
-	if (!masked)
-		unmask_evtchn(evtchn);
-
-	return 1;
-}
-
-int resend_irq_on_evtchn(unsigned int irq)
-{
-	return retrigger_evtchn(evtchn_from_irq(irq));
-}
-
 static void enable_dynirq(struct irq_data *data)
 {
 	int evtchn = evtchn_from_irq(data->irq);
@@ -1383,7 +1377,18 @@ static void mask_ack_dynirq(struct irq_data *data)
 
 static int retrigger_dynirq(struct irq_data *data)
 {
-	return retrigger_evtchn(evtchn_from_irq(data->irq));
+	unsigned int evtchn = evtchn_from_irq(data->irq);
+	int masked;
+
+	if (!VALID_EVTCHN(evtchn))
+		return 0;
+
+	masked = test_and_set_mask(evtchn);
+	set_evtchn(evtchn);
+	if (!masked)
+		unmask_evtchn(evtchn);
+
+	return 1;
 }
 
 static void restore_pirqs(void)
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 677f41a0fff9..50c2050a1e32 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -53,6 +53,7 @@ struct irq_info {
 
 #define PIRQ_NEEDS_EOI	(1 << 0)
 #define PIRQ_SHAREABLE	(1 << 1)
+#define PIRQ_MSI_GROUP	(1 << 2)
 
 struct evtchn_ops {
 	unsigned (*max_channels)(void);
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index b84e3ab839aa..6d325bda76da 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -933,9 +933,6 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 		    struct page **pages, unsigned int count)
 {
 	int i, ret;
-	bool lazy = false;
-	pte_t *pte;
-	unsigned long mfn;
 
 	ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
 	if (ret)
@@ -947,45 +944,7 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 			gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
 						&map_ops[i].status, __func__);
 
-	/* this is basically a nop on x86 */
-	if (xen_feature(XENFEAT_auto_translated_physmap)) {
-		for (i = 0; i < count; i++) {
-			if (map_ops[i].status)
-				continue;
-			set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
-					map_ops[i].dev_bus_addr >> PAGE_SHIFT);
-		}
-		return ret;
-	}
-
-	if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
-		arch_enter_lazy_mmu_mode();
-		lazy = true;
-	}
-
-	for (i = 0; i < count; i++) {
-		/* Do not add to override if the map failed. */
-		if (map_ops[i].status)
-			continue;
-
-		if (map_ops[i].flags & GNTMAP_contains_pte) {
-			pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
-				(map_ops[i].host_addr & ~PAGE_MASK));
-			mfn = pte_mfn(*pte);
-		} else {
-			mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
-		}
-		ret = m2p_add_override(mfn, pages[i], kmap_ops ?
-				       &kmap_ops[i] : NULL);
-		if (ret)
-			goto out;
-	}
-
- out:
-	if (lazy)
-		arch_leave_lazy_mmu_mode();
-
-	return ret;
+	return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
 }
 EXPORT_SYMBOL_GPL(gnttab_map_refs);
 
@@ -993,39 +952,13 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 		      struct gnttab_map_grant_ref *kmap_ops,
 		      struct page **pages, unsigned int count)
 {
-	int i, ret;
-	bool lazy = false;
+	int ret;
 
 	ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
 	if (ret)
 		return ret;
 
-	/* this is basically a nop on x86 */
-	if (xen_feature(XENFEAT_auto_translated_physmap)) {
-		for (i = 0; i < count; i++) {
-			set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
-					INVALID_P2M_ENTRY);
-		}
-		return ret;
-	}
-
-	if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
-		arch_enter_lazy_mmu_mode();
-		lazy = true;
-	}
-
-	for (i = 0; i < count; i++) {
-		ret = m2p_remove_override(pages[i], kmap_ops ?
-				       &kmap_ops[i] : NULL);
-		if (ret)
-			goto out;
-	}
-
- out:
-	if (lazy)
-		arch_leave_lazy_mmu_mode();
-
-	return ret;
+	return clear_foreign_p2m_mapping(unmap_ops, kmap_ops, pages, count);
 }
 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
 
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 624e8dc24532..32f9236c959f 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -46,6 +46,20 @@ struct suspend_info {
 	void (*post)(int cancelled);
 };
 
+static RAW_NOTIFIER_HEAD(xen_resume_notifier);
+
+void xen_resume_notifier_register(struct notifier_block *nb)
+{
+	raw_notifier_chain_register(&xen_resume_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
+
+void xen_resume_notifier_unregister(struct notifier_block *nb)
+{
+	raw_notifier_chain_unregister(&xen_resume_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
+
 #ifdef CONFIG_HIBERNATE_CALLBACKS
 static void xen_hvm_post_suspend(int cancelled)
 {
@@ -152,6 +166,8 @@ static void do_suspend(void)
 
 	err = stop_machine(xen_suspend, &si, cpumask_of(0));
 
+	raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
+
 	dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
 
 	if (err) {
@@ -182,10 +198,32 @@ 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)
@@ -291,6 +329,10 @@ 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;
@@ -301,6 +343,7 @@ static int setup_shutdown_watcher(void)
 		return err;
 	}
 
+
 #ifdef CONFIG_MAGIC_SYSRQ
 	err = register_xenbus_watch(&sysrq_watch);
 	if (err) {
@@ -329,6 +372,7 @@ int xen_setup_shutdown_event(void)
 	if (!xen_domain())
 		return -ENODEV;
 	register_xenstore_notifier(&xenstore_notifier);
+	register_reboot_notifier(&xen_reboot_nb);
 
 	return 0;
 }
diff --git a/drivers/xen/pcpu.c b/drivers/xen/pcpu.c
index 79e1dff7ed4f..0aac403d53fd 100644
--- a/drivers/xen/pcpu.c
+++ b/drivers/xen/pcpu.c
@@ -40,6 +40,7 @@
 #include <linux/capability.h>
 
 #include <xen/xen.h>
+#include <xen/acpi.h>
 #include <xen/xenbus.h>
 #include <xen/events.h>
 #include <xen/interface/platform.h>
diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
index a1361c312c06..3454973dc3bb 100644
--- a/drivers/xen/platform-pci.c
+++ b/drivers/xen/platform-pci.c
@@ -45,7 +45,7 @@ static unsigned long platform_mmio_alloc;
 static unsigned long platform_mmiolen;
 static uint64_t callback_via;
 
-unsigned long alloc_xen_mmio(unsigned long len)
+static unsigned long alloc_xen_mmio(unsigned long len)
 {
 	unsigned long addr;
 
diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
index 7231859119f1..82358d14ecf1 100644
--- a/drivers/xen/xen-acpi-processor.c
+++ b/drivers/xen/xen-acpi-processor.c
@@ -27,10 +27,10 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/types.h>
-#include <linux/syscore_ops.h>
 #include <linux/acpi.h>
 #include <acpi/processor.h>
 #include <xen/xen.h>
+#include <xen/xen-ops.h>
 #include <xen/interface/platform.h>
 #include <asm/xen/hypercall.h>
 
@@ -495,14 +495,15 @@ static int xen_upload_processor_pm_data(void)
 	return rc;
 }
 
-static void xen_acpi_processor_resume(void)
+static int xen_acpi_processor_resume(struct notifier_block *nb,
+				     unsigned long action, void *data)
 {
 	bitmap_zero(acpi_ids_done, nr_acpi_bits);
-	xen_upload_processor_pm_data();
+	return xen_upload_processor_pm_data();
 }
 
-static struct syscore_ops xap_syscore_ops = {
-	.resume	= xen_acpi_processor_resume,
+struct notifier_block xen_acpi_processor_resume_nb = {
+	.notifier_call = xen_acpi_processor_resume,
 };
 
 static int __init xen_acpi_processor_init(void)
@@ -555,7 +556,7 @@ static int __init xen_acpi_processor_init(void)
 	if (rc)
 		goto err_unregister;
 
-	register_syscore_ops(&xap_syscore_ops);
+	xen_resume_notifier_register(&xen_acpi_processor_resume_nb);
 
 	return 0;
 err_unregister:
@@ -574,7 +575,7 @@ static void __exit xen_acpi_processor_exit(void)
 {
 	int i;
 
-	unregister_syscore_ops(&xap_syscore_ops);
+	xen_resume_notifier_unregister(&xen_acpi_processor_resume_nb);
 	kfree(acpi_ids_done);
 	kfree(acpi_id_present);
 	kfree(acpi_id_cst_present);
diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c
index 64eb0cd8b8af..607e41460c0d 100644
--- a/drivers/xen/xen-pciback/pciback_ops.c
+++ b/drivers/xen/xen-pciback/pciback_ops.c
@@ -213,12 +213,11 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
 		entries[i].vector = op->msix_entries[i].vector;
 	}
 
-	result = pci_enable_msix(dev, entries, op->value);
-
+	result = pci_enable_msix_exact(dev, entries, op->value);
 	if (result == 0) {
 		for (i = 0; i < op->value; i++) {
 			op->msix_entries[i].entry = entries[i].entry;
-			if (entries[i].vector)
+			if (entries[i].vector) {
 				op->msix_entries[i].vector =
 					xen_pirq_from_irq(entries[i].vector);
 				if (unlikely(verbose_request))
@@ -226,6 +225,7 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
 						"MSI-X[%d]: %d\n",
 						pci_name(dev), i,
 						op->msix_entries[i].vector);
+			}
 		}
 	} else
 		pr_warn_ratelimited("%s: error enabling MSI-X for guest %u: err %d!\n",
diff --git a/drivers/xen/xen-pciback/vpci.c b/drivers/xen/xen-pciback/vpci.c
index 3165ce361b00..51afff96c515 100644
--- a/drivers/xen/xen-pciback/vpci.c
+++ b/drivers/xen/xen-pciback/vpci.c
@@ -137,6 +137,8 @@ unlock:
 	/* Publish this device. */
 	if (!err)
 		err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
+	else
+		kfree(dev_entry);
 
 out:
 	return err;
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
index 745ad79c1d8e..3b2bffde534f 100644
--- a/drivers/xen/xen-selfballoon.c
+++ b/drivers/xen/xen-selfballoon.c
@@ -170,6 +170,7 @@ static void frontswap_selfshrink(void)
 		tgt_frontswap_pages = cur_frontswap_pages -
 			(cur_frontswap_pages / frontswap_hysteresis);
 	frontswap_shrink(tgt_frontswap_pages);
+	frontswap_inertia_counter = frontswap_inertia;
 }
 
 #endif /* CONFIG_FRONTSWAP */
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 01d59e66565d..439c9dca9eee 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -401,33 +401,6 @@ EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
 
 
 /**
- * Bind to an existing interdomain event channel in another domain. Returns 0
- * on success and stores the local port in *port. On error, returns -errno,
- * switches the device to XenbusStateClosing, and saves the error in XenStore.
- */
-int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port)
-{
-	struct evtchn_bind_interdomain bind_interdomain;
-	int err;
-
-	bind_interdomain.remote_dom = dev->otherend_id;
-	bind_interdomain.remote_port = remote_port;
-
-	err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
-					  &bind_interdomain);
-	if (err)
-		xenbus_dev_fatal(dev, err,
-				 "binding to event channel %d from domain %d",
-				 remote_port, dev->otherend_id);
-	else
-		*port = bind_interdomain.local_port;
-
-	return err;
-}
-EXPORT_SYMBOL_GPL(xenbus_bind_evtchn);
-
-
-/**
  * Free an existing event channel. Returns 0 on success or -errno on error.
  */
 int xenbus_free_evtchn(struct xenbus_device *dev, int port)
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index b6d5fff43d16..ba804f3d8278 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -50,6 +50,7 @@
 #include <xen/xenbus.h>
 #include <xen/xen.h>
 #include "xenbus_comms.h"
+#include "xenbus_probe.h"
 
 struct xs_stored_msg {
 	struct list_head list;
@@ -139,6 +140,29 @@ static int get_error(const char *errorstring)
 	return xsd_errors[i].errnum;
 }
 
+static bool xenbus_ok(void)
+{
+	switch (xen_store_domain_type) {
+	case XS_LOCAL:
+		switch (system_state) {
+		case SYSTEM_POWER_OFF:
+		case SYSTEM_RESTART:
+		case SYSTEM_HALT:
+			return false;
+		default:
+			break;
+		}
+		return true;
+	case XS_PV:
+	case XS_HVM:
+		/* FIXME: Could check that the remote domain is alive,
+		 * but it is normally initial domain. */
+		return true;
+	default:
+		break;
+	}
+	return false;
+}
 static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len)
 {
 	struct xs_stored_msg *msg;
@@ -148,9 +172,20 @@ static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len)
 
 	while (list_empty(&xs_state.reply_list)) {
 		spin_unlock(&xs_state.reply_lock);
-		/* XXX FIXME: Avoid synchronous wait for response here. */
-		wait_event(xs_state.reply_waitq,
-			   !list_empty(&xs_state.reply_list));
+		if (xenbus_ok())
+			/* XXX FIXME: Avoid synchronous wait for response here. */
+			wait_event_timeout(xs_state.reply_waitq,
+					   !list_empty(&xs_state.reply_list),
+					   msecs_to_jiffies(500));
+		else {
+			/*
+			 * If we are in the process of being shut-down there is
+			 * no point of trying to contact XenBus - it is either
+			 * killed (xenstored application) or the other domain
+			 * has been killed or is unreachable.
+			 */
+			return ERR_PTR(-EIO);
+		}
 		spin_lock(&xs_state.reply_lock);
 	}
 
@@ -215,6 +250,9 @@ void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
 
 	mutex_unlock(&xs_state.request_mutex);
 
+	if (IS_ERR(ret))
+		return ret;
+
 	if ((msg->type == XS_TRANSACTION_END) ||
 	    ((req_msg.type == XS_TRANSACTION_START) &&
 	     (msg->type == XS_ERROR)))