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liberasurecode/src/backends/isa-l/isa_l_common.c

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/*
* Copyright 2014 Kevin M Greenan
* Copyright 2014 Tushar Gohad
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY
* THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* isa_l_rs_vand backend implementation
*
* vi: set noai tw=79 ts=4 sw=4:
*/
#include <stdio.h>
#include <stdlib.h>
#include "erasurecode.h"
#include "erasurecode_backend.h"
#include "erasurecode_helpers.h"
#include "erasurecode_helpers_ext.h"
#include "isa_l_common.h"
int isa_l_encode(void *desc, char **data, char **parity,
int blocksize)
{
isa_l_descriptor *isa_l_desc = (isa_l_descriptor*) desc;
unsigned char *g_tbls = NULL;
int k = isa_l_desc->k;
int m = isa_l_desc->m;
// Generate g_tbls from encode matrix encode_matrix
g_tbls = malloc(sizeof(unsigned char) * (k * m * 32));
if (NULL == g_tbls) {
return -1;
}
isa_l_desc->ec_init_tables(k, m, &isa_l_desc->matrix[k * k], g_tbls);
/* FIXME - make ec_encode_data return a value */
isa_l_desc->ec_encode_data(blocksize, k, m, g_tbls, (unsigned char**)data,
(unsigned char**)parity);
free(g_tbls);
return 0;
}
static unsigned char* isa_l_get_decode_matrix(int k, int m, unsigned char *encode_matrix, int *missing_idxs)
{
int i = 0, j = 0, l = 0;
int n = k + m;
unsigned char *decode_matrix = malloc(sizeof(unsigned char) * k * k);
uint64_t missing_bm = convert_list_to_bitmap(missing_idxs);
while (i < k && l < n) {
if (((1 << l) & missing_bm) == 0) {
for (j = 0; j < k; j++) {
decode_matrix[(k * i) + j] = encode_matrix[(k * l) + j];
}
i++;
}
l++;
}
if (i != k) {
free(decode_matrix);
decode_matrix = NULL;
}
return decode_matrix;
}
static int get_num_missing_elements(int *missing_idxs)
{
int i = 0;
while (missing_idxs[i] > -1) {
i++;
}
return i;
}
static void mult_and_xor_row(unsigned char *to_row,
unsigned char *from_row,
unsigned char val,
int num_elems,
gf_mul_func gf_mul)
{
int i;
for (i = 0; i < num_elems; i++) {
to_row[i] ^= gf_mul(val, from_row[i]);
}
}
/*
* TODO: Add in missing parity rows and adjust the inverse_rows to
* be used for parity.
*/
static unsigned char* get_inverse_rows(int k,
int m,
unsigned char *decode_inverse,
unsigned char* encode_matrix,
int *missing_idxs,
gf_mul_func gf_mul)
{
uint64_t missing_bm = convert_list_to_bitmap(missing_idxs);
int num_missing_elements = get_num_missing_elements(missing_idxs);
unsigned char *inverse_rows = (unsigned char*)malloc(sizeof(unsigned
char*) * k * num_missing_elements);
int i, j, l = 0;
int n = k + m;
if (NULL == inverse_rows) {
return NULL;
}
memset(inverse_rows, 0, sizeof(unsigned
char*) * k * num_missing_elements);
/*
* Fill in rows for missing data
*/
for (i = 0; i < k; i++) {
if ((1 << i) & missing_bm) {
for (j = 0; j < k; j++) {
inverse_rows[(l * k) + j] = decode_inverse[(i * k) + j];
}
l++;
}
}
/*
* Process missing parity.
*
* Start with an all-zero row.
*
* For each data element, if the data element is:
*
* Available: XOR the corresponding coefficient from the
* encoding matrix.
*
* Unavailable: multiply corresponding coefficient with
* the row that corresponds to the missing data in inverse_rows
* and XOR the resulting row with this row.
*/
for (i = k; i < n; i++) {
// Parity is missing
if ((1 << i) & missing_bm) {
int d_idx_avail = 0;
int d_idx_unavail = 0;
for (j = 0; j < k; j++) {
// This data is available, so we can use the encode matrix
if (((1 << j) & missing_bm) == 0) {
inverse_rows[(l * k) + d_idx_avail] ^= encode_matrix[(i * k) + j];
d_idx_avail++;
} else {
mult_and_xor_row(&inverse_rows[l * k],
&inverse_rows[d_idx_unavail * k],
encode_matrix[(i * k) + j],
k,
gf_mul);
d_idx_unavail++;
}
}
l++;
}
}
return inverse_rows;
}
int isa_l_decode(void *desc, char **data, char **parity,
int *missing_idxs, int blocksize)
{
isa_l_descriptor *isa_l_desc = (isa_l_descriptor*)desc;
unsigned char *g_tbls = NULL;
unsigned char *decode_matrix = NULL;
unsigned char *decode_inverse = NULL;
unsigned char *inverse_rows = NULL;
unsigned char **decoded_elements = NULL;
unsigned char **available_fragments = NULL;
int k = isa_l_desc->k;
int m = isa_l_desc->m;
int n = k + m;
int ret = -1;
int i, j;
int num_missing_elements = get_num_missing_elements(missing_idxs);
uint64_t missing_bm = convert_list_to_bitmap(missing_idxs);
decode_matrix = isa_l_get_decode_matrix(k, m, isa_l_desc->matrix, missing_idxs);
if (NULL == decode_matrix) {
goto out;
}
decode_inverse = (unsigned char*)malloc(sizeof(unsigned char) * k * k);
if (NULL == decode_inverse) {
goto out;
}
int im_ret = isa_l_desc->gf_invert_matrix(decode_matrix, decode_inverse, k);
if (im_ret < 0) {
goto out;
}
// Generate g_tbls from computed decode matrix (k x k) matrix
g_tbls = malloc(sizeof(unsigned char) * (k * m * 32));
if (NULL == g_tbls) {
goto out;
}
inverse_rows = get_inverse_rows(k, m, decode_inverse, isa_l_desc->matrix, missing_idxs, isa_l_desc->gf_mul);
decoded_elements = (unsigned char**)malloc(sizeof(unsigned char*)*num_missing_elements);
if (NULL == decoded_elements) {
goto out;
}
available_fragments = (unsigned char**)malloc(sizeof(unsigned char*)*k);
if (NULL == available_fragments) {
goto out;
}
j = 0;
for (i = 0; i < n; i++) {
if (missing_bm & (1 << i)) {
continue;
}
if (j == k) {
break;
}
if (i < k) {
available_fragments[j] = (unsigned char*)data[i];
} else {
available_fragments[j] = (unsigned char*)parity[i-k];
}
j++;
}
// Grab pointers to memory needed for missing data fragments
j = 0;
for (i = 0; i < k; i++) {
if (missing_bm & (1 << i)) {
decoded_elements[j] = (unsigned char*)data[i];
j++;
}
}
for (i = k; i < n; i++) {
if (missing_bm & (1 << i)) {
decoded_elements[j] = (unsigned char*)parity[i - k];
j++;
}
}
isa_l_desc->ec_init_tables(k, num_missing_elements, inverse_rows, g_tbls);
isa_l_desc->ec_encode_data(blocksize, k, num_missing_elements, g_tbls, (unsigned char**)available_fragments,
(unsigned char**)decoded_elements);
ret = 0;
out:
free(g_tbls);
free(decode_matrix);
free(decode_inverse);
free(inverse_rows);
free(decoded_elements);
free(available_fragments);
return ret;
}
int isa_l_reconstruct(void *desc, char **data, char **parity,
int *missing_idxs, int destination_idx, int blocksize)
{
isa_l_descriptor *isa_l_desc = (isa_l_descriptor*) desc;
unsigned char *g_tbls = NULL;
unsigned char *decode_matrix = NULL;
unsigned char *decode_inverse = NULL;
unsigned char *inverse_rows = NULL;
unsigned char *reconstruct_buf = NULL;
unsigned char **available_fragments = NULL;
int k = isa_l_desc->k;
int m = isa_l_desc->m;
int n = k + m;
int ret = -1;
int i, j;
uint64_t missing_bm = convert_list_to_bitmap(missing_idxs);
int inverse_row = -1;
/**
* Get available elements and compute the inverse of their
* corresponding rows.
*/
decode_matrix = isa_l_get_decode_matrix(k, m, isa_l_desc->matrix, missing_idxs);
if (NULL == decode_matrix) {
goto out;
}
decode_inverse = (unsigned char*)malloc(sizeof(unsigned char) * k * k);
if (NULL == decode_inverse) {
goto out;
}
int im_ret = isa_l_desc->gf_invert_matrix(decode_matrix, decode_inverse, k);
if (im_ret < 0) {
goto out;
}
/**
* Get the row needed to reconstruct
*/
inverse_rows = get_inverse_rows(k, m, decode_inverse, isa_l_desc->matrix, missing_idxs, isa_l_desc->gf_mul);
// Generate g_tbls from computed decode matrix (k x k) matrix
g_tbls = malloc(sizeof(unsigned char) * (k * m * 32));
if (NULL == g_tbls) {
goto out;
}
/**
* Fill in the available elements
*/
available_fragments = (unsigned char**)malloc(sizeof(unsigned char*)*k);
if (NULL == available_fragments) {
goto out;
}
j = 0;
for (i = 0; i < n; i++) {
if (missing_bm & (1 << i)) {
continue;
}
if (j == k) {
break;
}
if (i < k) {
available_fragments[j] = (unsigned char*)data[i];
} else {
available_fragments[j] = (unsigned char*)parity[i-k];
}
j++;
}
/**
* Copy pointer of buffer to reconstruct
*/
j = 0;
for (i = 0; i < n; i++) {
if (missing_bm & (1 << i)) {
if (i == destination_idx) {
if (i < k) {
reconstruct_buf = (unsigned char*)data[i];
} else {
reconstruct_buf = (unsigned char*)parity[i-k];
}
inverse_row = j;
break;
}
j++;
}
}
/**
* Do the reconstruction
*/
isa_l_desc->ec_init_tables(k, 1, &inverse_rows[inverse_row * k], g_tbls);
isa_l_desc->ec_encode_data(blocksize, k, 1, g_tbls, (unsigned char**)available_fragments,
(unsigned char**)&reconstruct_buf);
ret = 0;
out:
free(g_tbls);
free(decode_matrix);
free(decode_inverse);
free(inverse_rows);
free(available_fragments);
return ret;
}
int isa_l_min_fragments(void *desc, int *missing_idxs,
int *fragments_to_exclude, int *fragments_needed)
{
isa_l_descriptor *isa_l_desc = (isa_l_descriptor*)desc;
uint64_t exclude_bm = convert_list_to_bitmap(fragments_to_exclude);
uint64_t missing_bm = convert_list_to_bitmap(missing_idxs) | exclude_bm;
int i;
int j = 0;
int ret = -1;
for (i = 0; i < (isa_l_desc->k + isa_l_desc->m); i++) {
if (!(missing_bm & (1 << i))) {
fragments_needed[j] = i;
j++;
}
if (j == isa_l_desc->k) {
ret = 0;
fragments_needed[j] = -1;
break;
}
}
return ret;
}
/**
* Return the element-size, which is the number of bits stored
* on a given device, per codeword. This is always 8 in ISA-L
*
* Returns the size in bits!
*/
int isa_l_element_size(void* desc)
{
return 8;
}
int isa_l_exit(void *desc)
{
isa_l_descriptor *isa_l_desc = NULL;
isa_l_desc = (isa_l_descriptor*) desc;
free(isa_l_desc->matrix);
free(isa_l_desc);
return 0;
}
void * isa_l_common_init(struct ec_backend_args *args, void *backend_sohandle,
const char* gen_matrix_func_name)
{
isa_l_descriptor *desc = NULL;
desc = (isa_l_descriptor *)malloc(sizeof(isa_l_descriptor));
if (NULL == desc) {
return NULL;
}
desc->k = args->uargs.k;
desc->m = args->uargs.m;
if (args->uargs.w <= 0)
args->uargs.w = ISA_L_W;
desc->w = args->uargs.w;
/* validate EC arguments */
{
long long max_symbols = 1LL << desc->w;
if ((desc->k + desc->m) > max_symbols) {
goto error;
}
}
/*
* ISO C forbids casting a void* to a function pointer.
* Since dlsym return returns a void*, we use this union to
* "transform" the void* to a function pointer.
*/
union {
ec_encode_data_func encodep;
ec_init_tables_func init_tablesp;
gf_gen_encoding_matrix_func gen_matrixp;
gf_invert_matrix_func invert_matrixp;
gf_mul_func gf_mulp;
void *vptr;
} func_handle = {.vptr = NULL};
/* fill in function addresses */
func_handle.vptr = NULL;
func_handle.vptr = dlsym(backend_sohandle, "ec_encode_data");
desc->ec_encode_data = func_handle.encodep;
if (NULL == desc->ec_encode_data) {
goto error;
}
func_handle.vptr = NULL;
func_handle.vptr = dlsym(backend_sohandle, "ec_init_tables");
desc->ec_init_tables = func_handle.init_tablesp;
if (NULL == desc->ec_init_tables) {
goto error;
}
func_handle.vptr = NULL;
func_handle.vptr = dlsym(backend_sohandle, gen_matrix_func_name);
desc->gf_gen_encoding_matrix = func_handle.gen_matrixp;
if (NULL == desc->gf_gen_encoding_matrix) {
goto error;
}
func_handle.vptr = NULL;
func_handle.vptr = dlsym(backend_sohandle, "gf_invert_matrix");
desc->gf_invert_matrix = func_handle.invert_matrixp;
if (NULL == desc->gf_invert_matrix) {
goto error;
}
func_handle.vptr = NULL;
func_handle.vptr = dlsym(backend_sohandle, "gf_mul");
desc->gf_mul = func_handle.gf_mulp;
if (NULL == desc->gf_mul) {
goto error;
}
desc->matrix = malloc(sizeof(char) * desc->k * (desc->k + desc->m));
if (NULL == desc->matrix) {
goto error;
}
/**
* Generate ISA-L encoding matrix
* Note that this is an abstract func from each backend
*/
desc->gf_gen_encoding_matrix(desc->matrix, desc->k + desc->m, desc->k);
return desc;
error:
free(desc);
return NULL;
}
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