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kernel_optimize_test/crypto/async_tx/async_raid6_recov.c
Dan Williams 0403e38277 dmaengine: add fence support 
Some engines optimize operation by reading ahead in the descriptor chain
such that descriptor2 may start execution before descriptor1 completes.
If descriptor2 depends on the result from descriptor1 then a fence is
required (on descriptor2) to disable this optimization.  The async_tx
api could implicitly identify dependencies via the 'depend_tx'
parameter, but that would constrain cases where the dependency chain
only specifies a completion order rather than a data dependency.  So,
provide an ASYNC_TX_FENCE to explicitly identify data dependencies.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-09-08 17:42:50 -07:00

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/*
* Asynchronous RAID-6 recovery calculations ASYNC_TX API.
* Copyright(c) 2009 Intel Corporation
*
* based on raid6recov.c:
* Copyright 2002 H. Peter Anvin
*
* 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., 51
* Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/raid/pq.h>
#include <linux/async_tx.h>
static struct dma_async_tx_descriptor *
async_sum_product(struct page *dest, struct page **srcs, unsigned char *coef,
size_t len, struct async_submit_ctl *submit)
{
struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
&dest, 1, srcs, 2, len);
struct dma_device *dma = chan ? chan->device : NULL;
const u8 *amul, *bmul;
u8 ax, bx;
u8 *a, *b, *c;
if (dma) {
dma_addr_t dma_dest[2];
dma_addr_t dma_src[2];
struct device *dev = dma->dev;
struct dma_async_tx_descriptor *tx;
enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
if (submit->flags & ASYNC_TX_FENCE)
dma_flags |= DMA_PREP_FENCE;
dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
dma_src[0] = dma_map_page(dev, srcs[0], 0, len, DMA_TO_DEVICE);
dma_src[1] = dma_map_page(dev, srcs[1], 0, len, DMA_TO_DEVICE);
tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 2, coef,
len, dma_flags);
if (tx) {
async_tx_submit(chan, tx, submit);
return tx;
}
}
/* run the operation synchronously */
async_tx_quiesce(&submit->depend_tx);
amul = raid6_gfmul[coef[0]];
bmul = raid6_gfmul[coef[1]];
a = page_address(srcs[0]);
b = page_address(srcs[1]);
c = page_address(dest);
while (len--) {
ax = amul[*a++];
bx = bmul[*b++];
*c++ = ax ^ bx;
}
return NULL;
}
static struct dma_async_tx_descriptor *
async_mult(struct page *dest, struct page *src, u8 coef, size_t len,
struct async_submit_ctl *submit)
{
struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
&dest, 1, &src, 1, len);
struct dma_device *dma = chan ? chan->device : NULL;
const u8 *qmul; /* Q multiplier table */
u8 *d, *s;
if (dma) {
dma_addr_t dma_dest[2];
dma_addr_t dma_src[1];
struct device *dev = dma->dev;
struct dma_async_tx_descriptor *tx;
enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
if (submit->flags & ASYNC_TX_FENCE)
dma_flags |= DMA_PREP_FENCE;
dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
dma_src[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE);
tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 1, &coef,
len, dma_flags);
if (tx) {
async_tx_submit(chan, tx, submit);
return tx;
}
}
/* no channel available, or failed to allocate a descriptor, so
* perform the operation synchronously
*/
async_tx_quiesce(&submit->depend_tx);
qmul = raid6_gfmul[coef];
d = page_address(dest);
s = page_address(src);
while (len--)
*d++ = qmul[*s++];
return NULL;
}
static struct dma_async_tx_descriptor *
__2data_recov_4(size_t bytes, int faila, int failb, struct page **blocks,
struct async_submit_ctl *submit)
{
struct dma_async_tx_descriptor *tx = NULL;
struct page *p, *q, *a, *b;
struct page *srcs[2];
unsigned char coef[2];
enum async_tx_flags flags = submit->flags;
dma_async_tx_callback cb_fn = submit->cb_fn;
void *cb_param = submit->cb_param;
void *scribble = submit->scribble;
p = blocks[4-2];
q = blocks[4-1];
a = blocks[faila];
b = blocks[failb];
/* in the 4 disk case P + Pxy == P and Q + Qxy == Q */
/* Dx = A*(P+Pxy) + B*(Q+Qxy) */
srcs[0] = p;
srcs[1] = q;
coef[0] = raid6_gfexi[failb-faila];
coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_sum_product(b, srcs, coef, bytes, submit);
/* Dy = P+Pxy+Dx */
srcs[0] = p;
srcs[1] = b;
init_async_submit(submit, flags | ASYNC_TX_XOR_ZERO_DST, tx, cb_fn,
cb_param, scribble);
tx = async_xor(a, srcs, 0, 2, bytes, submit);
return tx;
}
static struct dma_async_tx_descriptor *
__2data_recov_5(size_t bytes, int faila, int failb, struct page **blocks,
struct async_submit_ctl *submit)
{
struct dma_async_tx_descriptor *tx = NULL;
struct page *p, *q, *g, *dp, *dq;
struct page *srcs[2];
unsigned char coef[2];
enum async_tx_flags flags = submit->flags;
dma_async_tx_callback cb_fn = submit->cb_fn;
void *cb_param = submit->cb_param;
void *scribble = submit->scribble;
int uninitialized_var(good);
int i;
for (i = 0; i < 3; i++) {
if (i == faila || i == failb)
continue;
else {
good = i;
break;
}
}
BUG_ON(i >= 3);
p = blocks[5-2];
q = blocks[5-1];
g = blocks[good];
/* Compute syndrome with zero for the missing data pages
* Use the dead data pages as temporary storage for delta p and
* delta q
*/
dp = blocks[faila];
dq = blocks[failb];
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_memcpy(dp, g, 0, 0, bytes, submit);
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
/* compute P + Pxy */
srcs[0] = dp;
srcs[1] = p;
init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
NULL, NULL, scribble);
tx = async_xor(dp, srcs, 0, 2, bytes, submit);
/* compute Q + Qxy */
srcs[0] = dq;
srcs[1] = q;
init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
NULL, NULL, scribble);
tx = async_xor(dq, srcs, 0, 2, bytes, submit);
/* Dx = A*(P+Pxy) + B*(Q+Qxy) */
srcs[0] = dp;
srcs[1] = dq;
coef[0] = raid6_gfexi[failb-faila];
coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_sum_product(dq, srcs, coef, bytes, submit);
/* Dy = P+Pxy+Dx */
srcs[0] = dp;
srcs[1] = dq;
init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
cb_param, scribble);
tx = async_xor(dp, srcs, 0, 2, bytes, submit);
return tx;
}
static struct dma_async_tx_descriptor *
__2data_recov_n(int disks, size_t bytes, int faila, int failb,
struct page **blocks, struct async_submit_ctl *submit)
{
struct dma_async_tx_descriptor *tx = NULL;
struct page *p, *q, *dp, *dq;
struct page *srcs[2];
unsigned char coef[2];
enum async_tx_flags flags = submit->flags;
dma_async_tx_callback cb_fn = submit->cb_fn;
void *cb_param = submit->cb_param;
void *scribble = submit->scribble;
p = blocks[disks-2];
q = blocks[disks-1];
/* Compute syndrome with zero for the missing data pages
* Use the dead data pages as temporary storage for
* delta p and delta q
*/
dp = blocks[faila];
blocks[faila] = (void *)raid6_empty_zero_page;
blocks[disks-2] = dp;
dq = blocks[failb];
blocks[failb] = (void *)raid6_empty_zero_page;
blocks[disks-1] = dq;
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
/* Restore pointer table */
blocks[faila] = dp;
blocks[failb] = dq;
blocks[disks-2] = p;
blocks[disks-1] = q;
/* compute P + Pxy */
srcs[0] = dp;
srcs[1] = p;
init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
NULL, NULL, scribble);
tx = async_xor(dp, srcs, 0, 2, bytes, submit);
/* compute Q + Qxy */
srcs[0] = dq;
srcs[1] = q;
init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
NULL, NULL, scribble);
tx = async_xor(dq, srcs, 0, 2, bytes, submit);
/* Dx = A*(P+Pxy) + B*(Q+Qxy) */
srcs[0] = dp;
srcs[1] = dq;
coef[0] = raid6_gfexi[failb-faila];
coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_sum_product(dq, srcs, coef, bytes, submit);
/* Dy = P+Pxy+Dx */
srcs[0] = dp;
srcs[1] = dq;
init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
cb_param, scribble);
tx = async_xor(dp, srcs, 0, 2, bytes, submit);
return tx;
}
/**
* async_raid6_2data_recov - asynchronously calculate two missing data blocks
* @disks: number of disks in the RAID-6 array
* @bytes: block size
* @faila: first failed drive index
* @failb: second failed drive index
* @blocks: array of source pointers where the last two entries are p and q
* @submit: submission/completion modifiers
*/
struct dma_async_tx_descriptor *
async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
struct page **blocks, struct async_submit_ctl *submit)
{
BUG_ON(faila == failb);
if (failb < faila)
swap(faila, failb);
pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
/* we need to preserve the contents of 'blocks' for the async
* case, so punt to synchronous if a scribble buffer is not available
*/
if (!submit->scribble) {
void **ptrs = (void **) blocks;
int i;
async_tx_quiesce(&submit->depend_tx);
for (i = 0; i < disks; i++)
ptrs[i] = page_address(blocks[i]);
raid6_2data_recov(disks, bytes, faila, failb, ptrs);
async_tx_sync_epilog(submit);
return NULL;
}
switch (disks) {
case 4:
/* dma devices do not uniformly understand a zero source pq
* operation (in contrast to the synchronous case), so
* explicitly handle the 4 disk special case
*/
return __2data_recov_4(bytes, faila, failb, blocks, submit);
case 5:
/* dma devices do not uniformly understand a single
* source pq operation (in contrast to the synchronous
* case), so explicitly handle the 5 disk special case
*/
return __2data_recov_5(bytes, faila, failb, blocks, submit);
default:
return __2data_recov_n(disks, bytes, faila, failb, blocks, submit);
}
}
EXPORT_SYMBOL_GPL(async_raid6_2data_recov);
/**
* async_raid6_datap_recov - asynchronously calculate a data and the 'p' block
* @disks: number of disks in the RAID-6 array
* @bytes: block size
* @faila: failed drive index
* @blocks: array of source pointers where the last two entries are p and q
* @submit: submission/completion modifiers
*/
struct dma_async_tx_descriptor *
async_raid6_datap_recov(int disks, size_t bytes, int faila,
struct page **blocks, struct async_submit_ctl *submit)
{
struct dma_async_tx_descriptor *tx = NULL;
struct page *p, *q, *dq;
u8 coef;
enum async_tx_flags flags = submit->flags;
dma_async_tx_callback cb_fn = submit->cb_fn;
void *cb_param = submit->cb_param;
void *scribble = submit->scribble;
struct page *srcs[2];
pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
/* we need to preserve the contents of 'blocks' for the async
* case, so punt to synchronous if a scribble buffer is not available
*/
if (!scribble) {
void **ptrs = (void **) blocks;
int i;
async_tx_quiesce(&submit->depend_tx);
for (i = 0; i < disks; i++)
ptrs[i] = page_address(blocks[i]);
raid6_datap_recov(disks, bytes, faila, ptrs);
async_tx_sync_epilog(submit);
return NULL;
}
p = blocks[disks-2];
q = blocks[disks-1];
/* Compute syndrome with zero for the missing data page
* Use the dead data page as temporary storage for delta q
*/
dq = blocks[faila];
blocks[faila] = (void *)raid6_empty_zero_page;
blocks[disks-1] = dq;
/* in the 4 disk case we only need to perform a single source
* multiplication
*/
if (disks == 4) {
int good = faila == 0 ? 1 : 0;
struct page *g = blocks[good];
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
scribble);
tx = async_memcpy(p, g, 0, 0, bytes, submit);
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
scribble);
tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
} else {
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
scribble);
tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
}
/* Restore pointer table */
blocks[faila] = dq;
blocks[disks-1] = q;
/* calculate g^{-faila} */
coef = raid6_gfinv[raid6_gfexp[faila]];
srcs[0] = dq;
srcs[1] = q;
init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
NULL, NULL, scribble);
tx = async_xor(dq, srcs, 0, 2, bytes, submit);
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_mult(dq, dq, coef, bytes, submit);
srcs[0] = p;
srcs[1] = dq;
init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
cb_param, scribble);
tx = async_xor(p, srcs, 0, 2, bytes, submit);
return tx;
}
EXPORT_SYMBOL_GPL(async_raid6_datap_recov);
MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>");
MODULE_DESCRIPTION("asynchronous RAID-6 recovery api");
MODULE_LICENSE("GPL");
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