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Commit 41e94a85 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dan Williams
Browse files

add devm_memremap_pages 



This behaves like devm_memremap except that it ensures we have page
structures available that can back the region.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
[djbw: catch attempts to remap RAM, drop flags]
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 033fbae9

include/linux/io.h

+20 −0
Original line number Diff line number Diff line
@@ -20,10 +20,13 @@ 


#include <linux/types.h>

#include <linux/init.h>

#include <linux/bug.h>

#include <linux/err.h>

#include <asm/io.h>

#include <asm/page.h>



struct device;

struct resource;



__visible void __iowrite32_copy(void __iomem *to, const void *from, size_t count);

void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
@@ -84,6 +87,23 @@ void *devm_memremap(struct device *dev, resource_size_t offset, 
		size_t size, unsigned long flags);

void devm_memunmap(struct device *dev, void *addr);



void *__devm_memremap_pages(struct device *dev, struct resource *res);



#ifdef CONFIG_ZONE_DEVICE

void *devm_memremap_pages(struct device *dev, struct resource *res);

#else

static inline void *devm_memremap_pages(struct device *dev, struct resource *res)

{

	/*

	 * Fail attempts to call devm_memremap_pages() without

	 * ZONE_DEVICE support enabled, this requires callers to fall

	 * back to plain devm_memremap() based on config

	 */

	WARN_ON_ONCE(1);

	return ERR_PTR(-ENXIO);

}

#endif



/*

 * Some systems do not have legacy ISA devices.

 * /dev/port is not a valid interface on these systems.

kernel/memremap.c

+53 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/types.h>

#include <linux/io.h>

#include <linux/mm.h>

#include <linux/memory_hotplug.h>



#ifndef ioremap_cache

/* temporary while we convert existing ioremap_cache users to memremap */
@@ -135,3 +136,55 @@ void devm_memunmap(struct device *dev, void *addr) 
	memunmap(addr);

}

EXPORT_SYMBOL(devm_memunmap);



#ifdef CONFIG_ZONE_DEVICE

struct page_map {

	struct resource res;

};



static void devm_memremap_pages_release(struct device *dev, void *res)

{

	struct page_map *page_map = res;



	/* pages are dead and unused, undo the arch mapping */

	arch_remove_memory(page_map->res.start, resource_size(&page_map->res));

}



void *devm_memremap_pages(struct device *dev, struct resource *res)

{

	int is_ram = region_intersects(res->start, resource_size(res),

			"System RAM");

	struct page_map *page_map;

	int error, nid;



	if (is_ram == REGION_MIXED) {

		WARN_ONCE(1, "%s attempted on mixed region %pr\n",

				__func__, res);

		return ERR_PTR(-ENXIO);

	}



	if (is_ram == REGION_INTERSECTS)

		return __va(res->start);



	page_map = devres_alloc(devm_memremap_pages_release,

			sizeof(*page_map), GFP_KERNEL);

	if (!page_map)

		return ERR_PTR(-ENOMEM);



	memcpy(&page_map->res, res, sizeof(*res));



	nid = dev_to_node(dev);

	if (nid < 0)

		nid = 0;



	error = arch_add_memory(nid, res->start, resource_size(res), true);

	if (error) {

		devres_free(page_map);

		return ERR_PTR(error);

	}



	devres_add(dev, page_map);

	return __va(res->start);

}

EXPORT_SYMBOL(devm_memremap_pages);

#endif /* CONFIG_ZONE_DEVICE */