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Commit cafaf14a authored by Chris Wilson's avatar Chris Wilson
Browse files

io-mapping: Always create a struct to hold metadata about the io-mapping 



Currently, we only allocate a structure to hold metadata if we need to
allocate an ioremap for every access, such as on x86-32. However, it
would be useful to store basic information about the io-mapping, such as
its page protection, on all platforms.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: linux-mm@kvack.org
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160819155428.1670-4-chris@chris-wilson.co.uk
parent 8678fdaf

include/linux/io-mapping.h

+57 −35
Original line number Diff line number Diff line
@@ -31,16 +31,16 @@ 
 * See Documentation/io-mapping.txt

 */



#ifdef CONFIG_HAVE_ATOMIC_IOMAP



#include <asm/iomap.h>



struct io_mapping {

	resource_size_t base;

	unsigned long size;

	pgprot_t prot;

	void __iomem *iomem;

};



#ifdef CONFIG_HAVE_ATOMIC_IOMAP



#include <asm/iomap.h>

/*

 * For small address space machines, mapping large objects

 * into the kernel virtual space isn't practical. Where
@@ -49,34 +49,25 @@ struct io_mapping { 
 */



static inline struct io_mapping *

io_mapping_create_wc(resource_size_t base, unsigned long size)

io_mapping_init_wc(struct io_mapping *iomap,

		   resource_size_t base,

		   unsigned long size)

{

	struct io_mapping *iomap;

	pgprot_t prot;



	iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);

	if (!iomap)

		goto out_err;



	if (iomap_create_wc(base, size, &prot))

		goto out_free;

		return NULL;



	iomap->base = base;

	iomap->size = size;

	iomap->prot = prot;

	return iomap;



out_free:

	kfree(iomap);

out_err:

	return NULL;

}



static inline void

io_mapping_free(struct io_mapping *mapping)

io_mapping_fini(struct io_mapping *mapping)

{

	iomap_free(mapping->base, mapping->size);

	kfree(mapping);

}



/* Atomic map/unmap */
@@ -121,21 +112,40 @@ io_mapping_unmap(void __iomem *vaddr) 
#else



#include <linux/uaccess.h>



/* this struct isn't actually defined anywhere */

struct io_mapping;

#include <asm/pgtable_types.h>



/* Create the io_mapping object*/

static inline struct io_mapping *

io_mapping_create_wc(resource_size_t base, unsigned long size)

io_mapping_init_wc(struct io_mapping *iomap,

		   resource_size_t base,

		   unsigned long size)

{

	return (struct io_mapping __force *) ioremap_wc(base, size);

	iomap->base = base;

	iomap->size = size;

	iomap->iomem = ioremap_wc(base, size);

	iomap->prot = pgprot_writecombine(PAGE_KERNEL_IO);



	return iomap;

}



static inline void

io_mapping_free(struct io_mapping *mapping)

io_mapping_fini(struct io_mapping *mapping)

{

	iounmap(mapping->iomem);

}



/* Non-atomic map/unmap */

static inline void __iomem *

io_mapping_map_wc(struct io_mapping *mapping,

		  unsigned long offset,

		  unsigned long size)

{

	return mapping->iomem + offset;

}



static inline void

io_mapping_unmap(void __iomem *vaddr)

{

	iounmap((void __force __iomem *) mapping);

}



/* Atomic map/unmap */
@@ -145,30 +155,42 @@ io_mapping_map_atomic_wc(struct io_mapping *mapping, 
{

	preempt_disable();

	pagefault_disable();

	return ((char __force __iomem *) mapping) + offset;

	return io_mapping_map_wc(mapping, offset, PAGE_SIZE);

}



static inline void

io_mapping_unmap_atomic(void __iomem *vaddr)

{

	io_mapping_unmap(vaddr);

	pagefault_enable();

	preempt_enable();

}



/* Non-atomic map/unmap */

static inline void __iomem *

io_mapping_map_wc(struct io_mapping *mapping,

		  unsigned long offset,

#endif /* HAVE_ATOMIC_IOMAP */



static inline struct io_mapping *

io_mapping_create_wc(resource_size_t base,

		     unsigned long size)

{

	return ((char __force __iomem *) mapping) + offset;

	struct io_mapping *iomap;



	iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);

	if (!iomap)

		return NULL;



	if (!io_mapping_init_wc(iomap, base, size)) {

		kfree(iomap);

		return NULL;

	}



	return iomap;

}



static inline void

io_mapping_unmap(void __iomem *vaddr)

io_mapping_free(struct io_mapping *iomap)

{

	io_mapping_fini(iomap);

	kfree(iomap);

}



#endif /* HAVE_ATOMIC_IOMAP */



#endif /* _LINUX_IO_MAPPING_H */