x86: Use syscore_ops instead of sysdev classes and sysdevs

Some subsystems in the x86 tree need to carry out suspend/resume and
shutdown operations with one CPU on-line and interrupts disabled and
they define sysdev classes and sysdevs or sysdev drivers for this
purpose.  This leads to unnecessarily complicated code and excessive
memory usage, so switch them to using struct syscore_ops objects for
this purpose instead.

Generally, there are three categories of subsystems that use
sysdevs for implementing PM operations: (1) subsystems whose
suspend/resume callbacks ignore their arguments entirely (the
majority), (2) subsystems whose suspend/resume callbacks use their
struct sys_device argument, but don't really need to do that,
because they can be implemented differently in an arguably simpler
way (io_apic.c), and (3) subsystems whose suspend/resume callbacks
use their struct sys_device argument, but the value of that argument
is always the same and could be ignored (microcode_core.c).  In all
of these cases the subsystems in question may be readily converted to
using struct syscore_ops objects for power management and shutdown.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 25 deletions

diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index c01ffa5b9b87..82ada01625b9 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -27,7 +27,7 @@
 #include <linux/kdebug.h>
 #include <linux/scatterlist.h>
 #include <linux/iommu-helper.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/io.h>
 #include <linux/gfp.h>
 #include <asm/atomic.h>
@@ -589,7 +589,7 @@ void set_up_gart_resume(u32 aper_order, u32 aper_alloc)
 	aperture_alloc = aper_alloc;
 }
 
-static void gart_fixup_northbridges(struct sys_device *dev)
+static void gart_fixup_northbridges(void)
 {
 	int i;
 
@@ -613,33 +613,20 @@ static void gart_fixup_northbridges(struct sys_device *dev)
 	}
 }
 
-static int gart_resume(struct sys_device *dev)
+static void gart_resume(void)
 {
 	pr_info("PCI-DMA: Resuming GART IOMMU\n");
 
-	gart_fixup_northbridges(dev);
+	gart_fixup_northbridges();
 
 	enable_gart_translations();
-
-	return 0;
 }
 
-static int gart_suspend(struct sys_device *dev, pm_message_t state)
-{
-	return 0;
-}
-
-static struct sysdev_class gart_sysdev_class = {
-	.name		= "gart",
-	.suspend	= gart_suspend,
+static struct syscore_ops gart_syscore_ops = {
 	.resume		= gart_resume,
 
 };
 
-static struct sys_device device_gart = {
-	.cls		= &gart_sysdev_class,
-};
-
 /*
  * Private Northbridge GATT initialization in case we cannot use the
  * AGP driver for some reason.
@@ -650,7 +637,7 @@ static __init int init_amd_gatt(struct agp_kern_info *info)
 	unsigned aper_base, new_aper_base;
 	struct pci_dev *dev;
 	void *gatt;
-	int i, error;
+	int i;
 
 	pr_info("PCI-DMA: Disabling AGP.\n");
 
@@ -685,12 +672,7 @@ static __init int init_amd_gatt(struct agp_kern_info *info)
 
 	agp_gatt_table = gatt;
 
-	error = sysdev_class_register(&gart_sysdev_class);
-	if (!error)
-		error = sysdev_register(&device_gart);
-	if (error)
-		panic("Could not register gart_sysdev -- "
-		      "would corrupt data on next suspend");
+	register_syscore_ops(&gart_syscore_ops);
 
 	flush_gart();