diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/flex_array.c | 398 |
2 files changed, 1 insertions, 399 deletions
diff --git a/lib/Makefile b/lib/Makefile index b798b41d01ae..4e066120a0d6 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -35,7 +35,7 @@ obj-y += lockref.o obj-y += bcd.o div64.o sort.o parser.o debug_locks.o random32.o \ bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \ - gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \ + gcd.o lcm.o list_sort.o uuid.o iov_iter.o clz_ctz.o \ bsearch.o find_bit.o llist.o memweight.o kfifo.o \ percpu-refcount.o rhashtable.o reciprocal_div.o \ once.o refcount.o usercopy.o errseq.o bucket_locks.o \ diff --git a/lib/flex_array.c b/lib/flex_array.c deleted file mode 100644 index 2eed22fa507c..000000000000 --- a/lib/flex_array.c +++ /dev/null @@ -1,398 +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/export.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 *flex_array_alloc(int element_size, unsigned int total, - gfp_t flags) -{ - struct flex_array *ret; - int elems_per_part = 0; - int max_size = 0; - struct reciprocal_value reciprocal_elems = { 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(flex_array_alloc); - -static int fa_element_to_part_nr(struct flex_array *fa, - unsigned int element_nr) -{ - /* - * if element_size == 0 we don't get here, so we never touch - * the zeroed fa->reciprocal_elems, which would yield invalid - * results - */ - 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 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(flex_array_free_parts); - -void flex_array_free(struct flex_array *fa) -{ - flex_array_free_parts(fa); - kfree(fa); -} -EXPORT_SYMBOL(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 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(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 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(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 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(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 *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(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 *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(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 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(flex_array_shrink); |