flex_array.h 1.27 KB
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#ifndef _FLEX_ARRAY_H
#define _FLEX_ARRAY_H

#include <linux/types.h>
#include <asm/page.h>

#define FLEX_ARRAY_PART_SIZE PAGE_SIZE
#define FLEX_ARRAY_BASE_SIZE PAGE_SIZE

struct flex_array_part;

/*
 * This is meant to replace cases where an array-like
 * structure has gotten too big to fit into kmalloc()
 * and the developer is getting tempted to use
 * vmalloc().
 */

struct flex_array {
	union {
		struct {
			int element_size;
			int total_nr_elements;
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			struct flex_array_part *parts[];
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		};
		/*
		 * This little trick makes sure that
		 * sizeof(flex_array) == PAGE_SIZE
		 */
		char padding[FLEX_ARRAY_BASE_SIZE];
	};
};

#define FLEX_ARRAY_INIT(size, total) { { {\
	.element_size = (size),		\
	.total_nr_elements = (total),	\
} } }

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struct flex_array *flex_array_alloc(int element_size, unsigned int total,
		gfp_t flags);
int flex_array_prealloc(struct flex_array *fa, unsigned int start,
		unsigned int end, gfp_t flags);
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void flex_array_free(struct flex_array *fa);
void flex_array_free_parts(struct flex_array *fa);
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int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
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		gfp_t flags);
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int flex_array_clear(struct flex_array *fa, unsigned int element_nr);
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void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
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#endif /* _FLEX_ARRAY_H */