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add devm_memremap_pages

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
[djbw: catch attempts to remap RAM, drop flags]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Christoph Hellwig 2015-08-17 16:00:35 +02:00 committed by Dan Williams
parent 033fbae988
commit 41e94a8513
2 changed files with 73 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

20
include/linux/io.h
View file

@ -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.

53
kernel/memremap.c
View file

@ -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 */