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#ifndef _LINUX_MEMREMAP_H_
#define _LINUX_MEMREMAP_H_
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/percpu-refcount.h>
struct resource;
struct device;
/**
* struct vmem_altmap - pre-allocated storage for vmemmap_populate
* @base_pfn: base of the entire dev_pagemap mapping
* @reserve: pages mapped, but reserved for driver use (relative to @base)
* @free: free pages set aside in the mapping for memmap storage
* @align: pages reserved to meet allocation alignments
* @alloc: track pages consumed, private to vmemmap_populate()
*/
struct vmem_altmap {
const unsigned long base_pfn;
const unsigned long reserve;
unsigned long free;
unsigned long align;
unsigned long alloc;
};
unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
#if defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_ZONE_DEVICE)
struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start);
#else
static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
{
return NULL;
}
#endif
/**
* struct dev_pagemap - metadata for ZONE_DEVICE mappings
* @altmap: pre-allocated/reserved memory for vmemmap allocations
* @res: physical address range covered by @ref
* @ref: reference count that pins the devm_memremap_pages() mapping
* @dev: host device of the mapping for debug
*/
struct dev_pagemap {
struct vmem_altmap *altmap;
const struct resource *res;
struct percpu_ref *ref;
struct device *dev;
};
#ifdef CONFIG_ZONE_DEVICE
void *devm_memremap_pages(struct device *dev, struct resource *res,
struct percpu_ref *ref, struct vmem_altmap *altmap);
struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
#else
static inline void *devm_memremap_pages(struct device *dev,
struct resource *res, struct percpu_ref *ref,
struct vmem_altmap *altmap)
{
/*
* 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);
}
static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
{
return NULL;
}
#endif
/**
* get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
* @pfn: page frame number to lookup page_map
* @pgmap: optional known pgmap that already has a reference
*
* @pgmap allows the overhead of a lookup to be bypassed when @pfn lands in the
* same mapping.
*/
static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap)
{
const struct resource *res = pgmap ? pgmap->res : NULL;
resource_size_t phys = PFN_PHYS(pfn);
/*
* In the cached case we're already holding a live reference so
* we can simply do a blind increment
*/
if (res && phys >= res->start && phys <= res->end) {
percpu_ref_get(pgmap->ref);
return pgmap;
}
/* fall back to slow path lookup */
rcu_read_lock();
pgmap = find_dev_pagemap(phys);
if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
pgmap = NULL;
rcu_read_unlock();
return pgmap;
}
static inline void put_dev_pagemap(struct dev_pagemap *pgmap)
{
if (pgmap)
percpu_ref_put(pgmap->ref);
}
#endif /* _LINUX_MEMREMAP_H_ */
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