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

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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: Chris Wilson <chris@chris-wilson.co.uk>
Cc: linux-mm@kvack.org
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160819155428.1670-4-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2016-08-19 16:54:26 +01:00
parent 8678fdaf39
commit cafaf14a5d
1 changed files with 57 additions and 35 deletions
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90
include/linux/io-mapping.h
View File

@ -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 */