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Commit 43339bed authored by Eli Billauer's avatar Eli Billauer Committed by Greg Kroah-Hartman
Browse files

devres: Add devm_get_free_pages API 



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

Signed-off-by: default avatarEli Billauer <eli.billauer@gmail.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8ffca9ea

Documentation/driver-model/devres.txt

+2 −0
Original line number Diff line number Diff line
@@ -237,6 +237,8 @@ MEM 
  devm_kzalloc()

  devm_kfree()

  devm_kmemdup()

  devm_get_free_pages()

  devm_free_pages()



IIO

  devm_iio_device_alloc()

drivers/base/devres.c

+76 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/device.h

+4 −0
Original line number Diff line number Diff line
@@ -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);