+++ /dev/null
-#include <linux/version.h>
-
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,0,0)
-
-/*
- * Flexible array managed in PAGE_SIZE parts
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright IBM Corporation, 2009
- *
- * Author: Dave Hansen <dave@linux.vnet.ibm.com>
- */
-
-#include <linux/flex_array.h>
-#include <linux/slab.h>
-#include <linux/stddef.h>
-#include <linux/module.h>
-#include <linux/reciprocal_div.h>
-
-struct flex_array_part {
- char elements[FLEX_ARRAY_PART_SIZE];
-};
-
-/*
- * If a user requests an allocation which is small
- * enough, we may simply use the space in the
- * flex_array->parts[] array to store the user
- * data.
- */
-static inline int elements_fit_in_base(struct flex_array *fa)
-{
- int data_size = fa->element_size * fa->total_nr_elements;
- if (data_size <= FLEX_ARRAY_BASE_BYTES_LEFT)
- return 1;
- return 0;
-}
-
-/**
- * flex_array_alloc - allocate a new flexible array
- * @element_size: the size of individual elements in the array
- * @total: total number of elements that this should hold
- * @flags: page allocation flags to use for base array
- *
- * Note: all locking must be provided by the caller.
- *
- * @total is used to size internal structures. If the user ever
- * accesses any array indexes >=@total, it will produce errors.
- *
- * The maximum number of elements is defined as: the number of
- * elements that can be stored in a page times the number of
- * page pointers that we can fit in the base structure or (using
- * integer math):
- *
- * (PAGE_SIZE/element_size) * (PAGE_SIZE-8)/sizeof(void *)
- *
- * Here's a table showing example capacities. Note that the maximum
- * index that the get/put() functions is just nr_objects-1. This
- * basically means that you get 4MB of storage on 32-bit and 2MB on
- * 64-bit.
- *
- *
- * Element size | Objects | Objects |
- * PAGE_SIZE=4k | 32-bit | 64-bit |
- * ---------------------------------|
- * 1 bytes | 4177920 | 2088960 |
- * 2 bytes | 2088960 | 1044480 |
- * 3 bytes | 1392300 | 696150 |
- * 4 bytes | 1044480 | 522240 |
- * 32 bytes | 130560 | 65408 |
- * 33 bytes | 126480 | 63240 |
- * 2048 bytes | 2040 | 1020 |
- * 2049 bytes | 1020 | 510 |
- * void * | 1044480 | 261120 |
- *
- * Since 64-bit pointers are twice the size, we lose half the
- * capacity in the base structure. Also note that no effort is made
- * to efficiently pack objects across page boundaries.
- */
-struct flex_array *rpl_flex_array_alloc(int element_size, unsigned int total,
- gfp_t flags)
-{
- struct flex_array *ret;
- struct reciprocal_value reciprocal_elems = {0};
- int elems_per_part = 0;
- int max_size = 0;
-
- if (element_size) {
- elems_per_part = FLEX_ARRAY_ELEMENTS_PER_PART(element_size);
- reciprocal_elems = reciprocal_value(elems_per_part);
- max_size = FLEX_ARRAY_NR_BASE_PTRS * elems_per_part;
- }
-
- /* max_size will end up 0 if element_size > PAGE_SIZE */
- if (total > max_size)
- return NULL;
- ret = kzalloc(sizeof(struct flex_array), flags);
- if (!ret)
- return NULL;
- ret->element_size = element_size;
- ret->total_nr_elements = total;
- ret->elems_per_part = elems_per_part;
- ret->reciprocal_elems = reciprocal_elems;
- if (elements_fit_in_base(ret) && !(flags & __GFP_ZERO))
- memset(&ret->parts[0], FLEX_ARRAY_FREE,
- FLEX_ARRAY_BASE_BYTES_LEFT);
- return ret;
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_alloc);
-
-static int fa_element_to_part_nr(struct flex_array *fa,
- unsigned int element_nr)
-{
- return reciprocal_divide(element_nr, fa->reciprocal_elems);
-}
-
-/**
- * flex_array_free_parts - just free the second-level pages
- * @fa: the flex array from which to free parts
- *
- * This is to be used in cases where the base 'struct flex_array'
- * has been statically allocated and should not be free.
- */
-void rpl_flex_array_free_parts(struct flex_array *fa)
-{
- int part_nr;
-
- if (elements_fit_in_base(fa))
- return;
- for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++)
- kfree(fa->parts[part_nr]);
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_free_parts);
-
-void rpl_flex_array_free(struct flex_array *fa)
-{
- flex_array_free_parts(fa);
- kfree(fa);
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_free);
-
-static unsigned int index_inside_part(struct flex_array *fa,
- unsigned int element_nr,
- unsigned int part_nr)
-{
- unsigned int part_offset;
-
- part_offset = element_nr - part_nr * fa->elems_per_part;
- return part_offset * fa->element_size;
-}
-
-static struct flex_array_part *
-__fa_get_part(struct flex_array *fa, int part_nr, gfp_t flags)
-{
- struct flex_array_part *part = fa->parts[part_nr];
- if (!part) {
- part = kmalloc(sizeof(struct flex_array_part), flags);
- if (!part)
- return NULL;
- if (!(flags & __GFP_ZERO))
- memset(part, FLEX_ARRAY_FREE,
- sizeof(struct flex_array_part));
- fa->parts[part_nr] = part;
- }
- return part;
-}
-
-/**
- * flex_array_put - copy data into the array at @element_nr
- * @fa: the flex array to copy data into
- * @element_nr: index of the position in which to insert
- * the new element.
- * @src: address of data to copy into the array
- * @flags: page allocation flags to use for array expansion
- *
- *
- * Note that this *copies* the contents of @src into
- * the array. If you are trying to store an array of
- * pointers, make sure to pass in &ptr instead of ptr.
- * You may instead wish to use the flex_array_put_ptr()
- * helper function.
- *
- * Locking must be provided by the caller.
- */
-int rpl_flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
- gfp_t flags)
-{
- int part_nr = 0;
- struct flex_array_part *part;
- void *dst;
-
- if (element_nr >= fa->total_nr_elements)
- return -ENOSPC;
- if (!fa->element_size)
- return 0;
- if (elements_fit_in_base(fa))
- part = (struct flex_array_part *)&fa->parts[0];
- else {
- part_nr = fa_element_to_part_nr(fa, element_nr);
- part = __fa_get_part(fa, part_nr, flags);
- if (!part)
- return -ENOMEM;
- }
- dst = &part->elements[index_inside_part(fa, element_nr, part_nr)];
- memcpy(dst, src, fa->element_size);
- return 0;
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_put);
-
-/**
- * flex_array_clear - clear element in array at @element_nr
- * @fa: the flex array of the element.
- * @element_nr: index of the position to clear.
- *
- * Locking must be provided by the caller.
- */
-int rpl_flex_array_clear(struct flex_array *fa, unsigned int element_nr)
-{
- int part_nr = 0;
- struct flex_array_part *part;
- void *dst;
-
- if (element_nr >= fa->total_nr_elements)
- return -ENOSPC;
- if (!fa->element_size)
- return 0;
- if (elements_fit_in_base(fa))
- part = (struct flex_array_part *)&fa->parts[0];
- else {
- part_nr = fa_element_to_part_nr(fa, element_nr);
- part = fa->parts[part_nr];
- if (!part)
- return -EINVAL;
- }
- dst = &part->elements[index_inside_part(fa, element_nr, part_nr)];
- memset(dst, FLEX_ARRAY_FREE, fa->element_size);
- return 0;
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_clear);
-
-/**
- * flex_array_prealloc - guarantee that array space exists
- * @fa: the flex array for which to preallocate parts
- * @start: index of first array element for which space is
- * allocated
- * @nr_elements: number of elements for which space is allocated
- * @flags: page allocation flags
- *
- * This will guarantee that no future calls to flex_array_put()
- * will allocate memory. It can be used if you are expecting to
- * be holding a lock or in some atomic context while writing
- * data into the array.
- *
- * Locking must be provided by the caller.
- */
-int rpl_flex_array_prealloc(struct flex_array *fa, unsigned int start,
- unsigned int nr_elements, gfp_t flags)
-{
- int start_part;
- int end_part;
- int part_nr;
- unsigned int end;
- struct flex_array_part *part;
-
- if (!start && !nr_elements)
- return 0;
- if (start >= fa->total_nr_elements)
- return -ENOSPC;
- if (!nr_elements)
- return 0;
-
- end = start + nr_elements - 1;
-
- if (end >= fa->total_nr_elements)
- return -ENOSPC;
- if (!fa->element_size)
- return 0;
- if (elements_fit_in_base(fa))
- return 0;
- start_part = fa_element_to_part_nr(fa, start);
- end_part = fa_element_to_part_nr(fa, end);
- for (part_nr = start_part; part_nr <= end_part; part_nr++) {
- part = __fa_get_part(fa, part_nr, flags);
- if (!part)
- return -ENOMEM;
- }
- return 0;
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_prealloc);
-
-/**
- * flex_array_get - pull data back out of the array
- * @fa: the flex array from which to extract data
- * @element_nr: index of the element to fetch from the array
- *
- * Returns a pointer to the data at index @element_nr. Note
- * that this is a copy of the data that was passed in. If you
- * are using this to store pointers, you'll get back &ptr. You
- * may instead wish to use the flex_array_get_ptr helper.
- *
- * Locking must be provided by the caller.
- */
-void *rpl_flex_array_get(struct flex_array *fa, unsigned int element_nr)
-{
- int part_nr = 0;
- struct flex_array_part *part;
-
- if (!fa->element_size)
- return NULL;
- if (element_nr >= fa->total_nr_elements)
- return NULL;
- if (elements_fit_in_base(fa))
- part = (struct flex_array_part *)&fa->parts[0];
- else {
- part_nr = fa_element_to_part_nr(fa, element_nr);
- part = fa->parts[part_nr];
- if (!part)
- return NULL;
- }
- return &part->elements[index_inside_part(fa, element_nr, part_nr)];
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_get);
-
-/**
- * flex_array_get_ptr - pull a ptr back out of the array
- * @fa: the flex array from which to extract data
- * @element_nr: index of the element to fetch from the array
- *
- * Returns the pointer placed in the flex array at element_nr using
- * flex_array_put_ptr(). This function should not be called if the
- * element in question was not set using the _put_ptr() helper.
- */
-void *rpl_flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr)
-{
- void **tmp;
-
- tmp = flex_array_get(fa, element_nr);
- if (!tmp)
- return NULL;
-
- return *tmp;
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_get_ptr);
-
-static int part_is_free(struct flex_array_part *part)
-{
- int i;
-
- for (i = 0; i < sizeof(struct flex_array_part); i++)
- if (part->elements[i] != FLEX_ARRAY_FREE)
- return 0;
- return 1;
-}
-
-/**
- * flex_array_shrink - free unused second-level pages
- * @fa: the flex array to shrink
- *
- * Frees all second-level pages that consist solely of unused
- * elements. Returns the number of pages freed.
- *
- * Locking must be provided by the caller.
- */
-int rpl_flex_array_shrink(struct flex_array *fa)
-{
- struct flex_array_part *part;
- int part_nr;
- int ret = 0;
-
- if (!fa->total_nr_elements || !fa->element_size)
- return 0;
- if (elements_fit_in_base(fa))
- return ret;
- for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++) {
- part = fa->parts[part_nr];
- if (!part)
- continue;
- if (part_is_free(part)) {
- fa->parts[part_nr] = NULL;
- kfree(part);
- ret++;
- }
- }
- return ret;
-}
-EXPORT_SYMBOL_GPL(rpl_flex_array_shrink);
-
-#endif /* Linux version < 3.0.0 */
+++ /dev/null
-#ifndef __LINUX_FLEX_ARRAY_WRAPPER_H
-#define __LINUX_FLEX_ARRAY_WRAPPER_H
-
-#include <linux/version.h>
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,0,0)
-#include_next <linux/flex_array.h>
-#else
-
-#include <linux/reciprocal_div.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;
- int elems_per_part;
- struct reciprocal_value reciprocal_elems;
- struct flex_array_part *parts[];
- };
- /*
- * This little trick makes sure that
- * sizeof(flex_array) == PAGE_SIZE
- */
- char padding[FLEX_ARRAY_BASE_SIZE];
- };
-};
-
-/* Number of bytes left in base struct flex_array, excluding metadata */
-#define FLEX_ARRAY_BASE_BYTES_LEFT \
- (FLEX_ARRAY_BASE_SIZE - offsetof(struct flex_array, parts))
-
-/* Number of pointers in base to struct flex_array_part pages */
-#define FLEX_ARRAY_NR_BASE_PTRS \
- (FLEX_ARRAY_BASE_BYTES_LEFT / sizeof(struct flex_array_part *))
-
-/* Number of elements of size that fit in struct flex_array_part */
-#define FLEX_ARRAY_ELEMENTS_PER_PART(size) \
- (FLEX_ARRAY_PART_SIZE / size)
-
-/*
- * Defines a statically allocated flex array and ensures its parameters are
- * valid.
- */
-#define DEFINE_FLEX_ARRAY(__arrayname, __element_size, __total) \
- struct flex_array __arrayname = { { { \
- .element_size = (__element_size), \
- .total_nr_elements = (__total), \
- } } }; \
- static inline void __arrayname##_invalid_parameter(void) \
- { \
- BUILD_BUG_ON((__total) > FLEX_ARRAY_NR_BASE_PTRS * \
- FLEX_ARRAY_ELEMENTS_PER_PART(__element_size)); \
- }
-
-#define flex_array_alloc rpl_flex_array_alloc
-struct flex_array *rpl_flex_array_alloc(int element_size, unsigned int total,
- gfp_t flags);
-
-#define flex_array_prealloc rpl_flex_array_prealloc
-int rpl_flex_array_prealloc(struct flex_array *fa, unsigned int start,
- unsigned int nr_elements, gfp_t flags);
-
-#define flex_array_free rpl_flex_array_free
-void rpl_flex_array_free(struct flex_array *fa);
-
-#define flex_array_free_parts rpl_flex_array_free_parts
-void rpl_flex_array_free_parts(struct flex_array *fa);
-
-#define flex_array_put rpl_flex_array_put
-int rpl_flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
- gfp_t flags);
-
-#define flex_array_clear rpl_flex_array_clear
-int rpl_flex_array_clear(struct flex_array *fa, unsigned int element_nr);
-
-#define flex_array_get rpl_flex_array_get
-void *rpl_flex_array_get(struct flex_array *fa, unsigned int element_nr);
-
-#define flex_array_shrink rpl_flex_array_shrink
-int rpl_flex_array_shrink(struct flex_array *fa);
-
-#define flex_array_put_ptr rpl_flex_array_put_ptr
-#define rpl_flex_array_put_ptr(fa, nr, src, gfp) \
- flex_array_put(fa, nr, (void *)&(src), gfp)
-
-#define flex_array_get_ptr rpl_flex_array_get_ptr
-void *rpl_flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr);
-
-#endif /* Linux version < 3.0.0 */
-#endif /* __LINUX_FLEX_ARRAY_WRAPPER_H */
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