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devres: Add devm_get_free_pages API

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devm_get_free_pages() and devm_free_pages() are the managed counterparts
for __get_free_pages() and free_pages().

Signed-off-by: Eli Billauer <eli.billauer@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eli Billauer 2014-05-16 11:26:35 +03:00 committed by Greg Kroah-Hartman
parent 8ffca9eae6
commit 43339bed70
3 changed files with 82 additions and 0 deletions
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2
Documentation/driver-model/devres.txt
View File

@ -237,6 +237,8 @@ MEM
devm_kzalloc()
devm_kfree()
devm_kmemdup()
devm_get_free_pages()
devm_free_pages()
IIO
devm_iio_device_alloc()

76
drivers/base/devres.c
View File

@ -852,3 +852,79 @@ void *devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp)
return p;
}
EXPORT_SYMBOL_GPL(devm_kmemdup);
struct pages_devres {
unsigned long addr;
unsigned int order;
};
static int devm_pages_match(struct device *dev, void *res, void *p)
{
struct pages_devres *devres = res;
struct pages_devres *target = p;
return devres->addr == target->addr;
}
static void devm_pages_release(struct device *dev, void *res)
{
struct pages_devres *devres = res;
free_pages(devres->addr, devres->order);
}
/**
* devm_get_free_pages - Resource-managed __get_free_pages
* @dev: Device to allocate memory for
* @gfp_mask: Allocation gfp flags
* @order: Allocation size is (1 << order) pages
*
* Managed get_free_pages. Memory allocated with this function is
* automatically freed on driver detach.
*
* RETURNS:
* Address of allocated memory on success, 0 on failure.
*/
unsigned long devm_get_free_pages(struct device *dev,
gfp_t gfp_mask, unsigned int order)
{
struct pages_devres *devres;
unsigned long addr;
addr = __get_free_pages(gfp_mask, order);
if (unlikely(!addr))
return 0;
devres = devres_alloc(devm_pages_release,
sizeof(struct pages_devres), GFP_KERNEL);
if (unlikely(!devres)) {
free_pages(addr, order);
return 0;
}
devres->addr = addr;
devres->order = order;
devres_add(dev, devres);
return addr;
}
EXPORT_SYMBOL_GPL(devm_get_free_pages);
/**
* devm_free_pages - Resource-managed free_pages
* @dev: Device this memory belongs to
* @addr: Memory to free
*
* Free memory allocated with devm_get_free_pages(). Unlike free_pages,
* there is no need to supply the @order.
*/
void devm_free_pages(struct device *dev, unsigned long addr)
{
struct pages_devres devres = { .addr = addr };
WARN_ON(devres_release(dev, devm_pages_release, devm_pages_match,
&devres));
}
EXPORT_SYMBOL_GPL(devm_free_pages);

4
include/linux/device.h
View File

@ -626,6 +626,10 @@ extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp);
extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
gfp_t gfp);
extern unsigned long devm_get_free_pages(struct device *dev,
gfp_t gfp_mask, unsigned int order);
extern void devm_free_pages(struct device *dev, unsigned long addr);
void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
void __iomem *devm_request_and_ioremap(struct device *dev,
struct resource *res);