[ARM] Add a reference from struct device to the dma bounce info

dmabounce keeps a per-device structure, and finds the correct
structure by walking a list. Since architectures can now add
fields to struct device, we can attach this structure direct to
the struct device, thereby eliminating the code to search the
list.

Signed-off-by: Russell King <[e-mail]>

arch/arm/common/dmabounce.c

···
 };
 
 struct dmabounce_device_info {
-	struct list_head node;
-
 	struct device *dev;
 	struct list_head safe_buffers;
 #ifdef STATS
···
 	rwlock_t lock;
 };
 
-static LIST_HEAD(dmabounce_devs);
-
 #ifdef STATS
 static void print_alloc_stats(struct dmabounce_device_info *device_info)
 {
···
 		device_info->total_allocs);
 }
 #endif
-
-/* find the given device in the dmabounce device list */
-static inline struct dmabounce_device_info *
-find_dmabounce_dev(struct device *dev)
-{
-	struct dmabounce_device_info *d;
-
-	list_for_each_entry(d, &dmabounce_devs, node)
-		if (d->dev == dev)
-			return d;
-
-	return NULL;
-}
 
 
 /* allocate a 'safe' buffer and keep track of it */
···
 map_single(struct device *dev, void *ptr, size_t size,
 		enum dma_data_direction dir)
 {
-	struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
+	struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
 	dma_addr_t dma_addr;
 	int needs_bounce = 0;
 
···
 unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
 		enum dma_data_direction dir)
 {
-	struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
+	struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
 	struct safe_buffer *buf = NULL;
 
 	/*
···
 sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
 		enum dma_data_direction dir)
 {
-	struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
+	struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
 	struct safe_buffer *buf = NULL;
 
 	if (device_info)
···
 	device_info->bounce_count = 0;
 #endif
 
-	list_add(&device_info->node, &dmabounce_devs);
+	dev->archdata.dmabounce = device_info;
 
 	printk(KERN_INFO "dmabounce: registered device %s on %s bus\n",
 		dev->bus_id, dev->bus->name);
···
 void
 dmabounce_unregister_dev(struct device *dev)
 {
-	struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
+	struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
+
+	dev->archdata.dmabounce = NULL;
 
 	if (!device_info) {
 		printk(KERN_WARNING
···
 	print_alloc_stats(device_info);
 	print_map_stats(device_info);
 #endif
-
-	list_del(&device_info->node);
 
 	kfree(device_info);
 

include/asm-arm/device.h

···
  *
  * This file is released under the GPLv2
  */
-#include <asm-generic/device.h>
+#ifndef ASMARM_DEVICE_H
+#define ASMARM_DEVICE_H
 
+struct dev_archdata {
+#ifdef CONFIG_DMABOUNCE
+	struct dmabounce_device_info *dmabounce;
+#endif
+};
+
+#endif