linux/crypto/async_tx/async_xor.c
Paul Gortmaker 4bb33cc890 crypto: add module.h to those files that are explicitly using it
Part of the include cleanups means that the implicit
inclusion of module.h via device.h is going away.  So
fix things up in advance.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:31:11 -04:00

340 lines
9.9 KiB
C

/*
* xor offload engine api
*
* Copyright © 2006, Intel Corporation.
*
* Dan Williams <dan.j.williams@intel.com>
*
* with architecture considerations by:
* Neil Brown <neilb@suse.de>
* Jeff Garzik <jeff@garzik.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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/module.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/raid/xor.h>
#include <linux/async_tx.h>
/* do_async_xor - dma map the pages and perform the xor with an engine */
static __async_inline struct dma_async_tx_descriptor *
do_async_xor(struct dma_chan *chan, struct page *dest, struct page **src_list,
unsigned int offset, int src_cnt, size_t len, dma_addr_t *dma_src,
struct async_submit_ctl *submit)
{
struct dma_device *dma = chan->device;
struct dma_async_tx_descriptor *tx = NULL;
int src_off = 0;
int i;
dma_async_tx_callback cb_fn_orig = submit->cb_fn;
void *cb_param_orig = submit->cb_param;
enum async_tx_flags flags_orig = submit->flags;
enum dma_ctrl_flags dma_flags;
int xor_src_cnt = 0;
dma_addr_t dma_dest;
/* map the dest bidrectional in case it is re-used as a source */
dma_dest = dma_map_page(dma->dev, dest, offset, len, DMA_BIDIRECTIONAL);
for (i = 0; i < src_cnt; i++) {
/* only map the dest once */
if (!src_list[i])
continue;
if (unlikely(src_list[i] == dest)) {
dma_src[xor_src_cnt++] = dma_dest;
continue;
}
dma_src[xor_src_cnt++] = dma_map_page(dma->dev, src_list[i], offset,
len, DMA_TO_DEVICE);
}
src_cnt = xor_src_cnt;
while (src_cnt) {
submit->flags = flags_orig;
dma_flags = 0;
xor_src_cnt = min(src_cnt, (int)dma->max_xor);
/* if we are submitting additional xors, leave the chain open,
* clear the callback parameters, and leave the destination
* buffer mapped
*/
if (src_cnt > xor_src_cnt) {
submit->flags &= ~ASYNC_TX_ACK;
submit->flags |= ASYNC_TX_FENCE;
dma_flags = DMA_COMPL_SKIP_DEST_UNMAP;
submit->cb_fn = NULL;
submit->cb_param = NULL;
} else {
submit->cb_fn = cb_fn_orig;
submit->cb_param = cb_param_orig;
}
if (submit->cb_fn)
dma_flags |= DMA_PREP_INTERRUPT;
if (submit->flags & ASYNC_TX_FENCE)
dma_flags |= DMA_PREP_FENCE;
/* Since we have clobbered the src_list we are committed
* to doing this asynchronously. Drivers force forward progress
* in case they can not provide a descriptor
*/
tx = dma->device_prep_dma_xor(chan, dma_dest, &dma_src[src_off],
xor_src_cnt, len, dma_flags);
if (unlikely(!tx))
async_tx_quiesce(&submit->depend_tx);
/* spin wait for the preceding transactions to complete */
while (unlikely(!tx)) {
dma_async_issue_pending(chan);
tx = dma->device_prep_dma_xor(chan, dma_dest,
&dma_src[src_off],
xor_src_cnt, len,
dma_flags);
}
async_tx_submit(chan, tx, submit);
submit->depend_tx = tx;
if (src_cnt > xor_src_cnt) {
/* drop completed sources */
src_cnt -= xor_src_cnt;
src_off += xor_src_cnt;
/* use the intermediate result a source */
dma_src[--src_off] = dma_dest;
src_cnt++;
} else
break;
}
return tx;
}
static void
do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
int src_cnt, size_t len, struct async_submit_ctl *submit)
{
int i;
int xor_src_cnt = 0;
int src_off = 0;
void *dest_buf;
void **srcs;
if (submit->scribble)
srcs = submit->scribble;
else
srcs = (void **) src_list;
/* convert to buffer pointers */
for (i = 0; i < src_cnt; i++)
if (src_list[i])
srcs[xor_src_cnt++] = page_address(src_list[i]) + offset;
src_cnt = xor_src_cnt;
/* set destination address */
dest_buf = page_address(dest) + offset;
if (submit->flags & ASYNC_TX_XOR_ZERO_DST)
memset(dest_buf, 0, len);
while (src_cnt > 0) {
/* process up to 'MAX_XOR_BLOCKS' sources */
xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
xor_blocks(xor_src_cnt, len, dest_buf, &srcs[src_off]);
/* drop completed sources */
src_cnt -= xor_src_cnt;
src_off += xor_src_cnt;
}
async_tx_sync_epilog(submit);
}
/**
* async_xor - attempt to xor a set of blocks with a dma engine.
* @dest: destination page
* @src_list: array of source pages
* @offset: common src/dst offset to start transaction
* @src_cnt: number of source pages
* @len: length in bytes
* @submit: submission / completion modifiers
*
* honored flags: ASYNC_TX_ACK, ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DST
*
* xor_blocks always uses the dest as a source so the
* ASYNC_TX_XOR_ZERO_DST flag must be set to not include dest data in
* the calculation. The assumption with dma eninges is that they only
* use the destination buffer as a source when it is explicity specified
* in the source list.
*
* src_list note: if the dest is also a source it must be at index zero.
* The contents of this array will be overwritten if a scribble region
* is not specified.
*/
struct dma_async_tx_descriptor *
async_xor(struct page *dest, struct page **src_list, unsigned int offset,
int src_cnt, size_t len, struct async_submit_ctl *submit)
{
struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR,
&dest, 1, src_list,
src_cnt, len);
dma_addr_t *dma_src = NULL;
BUG_ON(src_cnt <= 1);
if (submit->scribble)
dma_src = submit->scribble;
else if (sizeof(dma_addr_t) <= sizeof(struct page *))
dma_src = (dma_addr_t *) src_list;
if (dma_src && chan && is_dma_xor_aligned(chan->device, offset, 0, len)) {
/* run the xor asynchronously */
pr_debug("%s (async): len: %zu\n", __func__, len);
return do_async_xor(chan, dest, src_list, offset, src_cnt, len,
dma_src, submit);
} else {
/* run the xor synchronously */
pr_debug("%s (sync): len: %zu\n", __func__, len);
WARN_ONCE(chan, "%s: no space for dma address conversion\n",
__func__);
/* in the sync case the dest is an implied source
* (assumes the dest is the first source)
*/
if (submit->flags & ASYNC_TX_XOR_DROP_DST) {
src_cnt--;
src_list++;
}
/* wait for any prerequisite operations */
async_tx_quiesce(&submit->depend_tx);
do_sync_xor(dest, src_list, offset, src_cnt, len, submit);
return NULL;
}
}
EXPORT_SYMBOL_GPL(async_xor);
static int page_is_zero(struct page *p, unsigned int offset, size_t len)
{
char *a = page_address(p) + offset;
return ((*(u32 *) a) == 0 &&
memcmp(a, a + 4, len - 4) == 0);
}
static inline struct dma_chan *
xor_val_chan(struct async_submit_ctl *submit, struct page *dest,
struct page **src_list, int src_cnt, size_t len)
{
#ifdef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
return NULL;
#endif
return async_tx_find_channel(submit, DMA_XOR_VAL, &dest, 1, src_list,
src_cnt, len);
}
/**
* async_xor_val - attempt a xor parity check with a dma engine.
* @dest: destination page used if the xor is performed synchronously
* @src_list: array of source pages
* @offset: offset in pages to start transaction
* @src_cnt: number of source pages
* @len: length in bytes
* @result: 0 if sum == 0 else non-zero
* @submit: submission / completion modifiers
*
* honored flags: ASYNC_TX_ACK
*
* src_list note: if the dest is also a source it must be at index zero.
* The contents of this array will be overwritten if a scribble region
* is not specified.
*/
struct dma_async_tx_descriptor *
async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
int src_cnt, size_t len, enum sum_check_flags *result,
struct async_submit_ctl *submit)
{
struct dma_chan *chan = xor_val_chan(submit, dest, src_list, src_cnt, len);
struct dma_device *device = chan ? chan->device : NULL;
struct dma_async_tx_descriptor *tx = NULL;
dma_addr_t *dma_src = NULL;
BUG_ON(src_cnt <= 1);
if (submit->scribble)
dma_src = submit->scribble;
else if (sizeof(dma_addr_t) <= sizeof(struct page *))
dma_src = (dma_addr_t *) src_list;
if (dma_src && device && src_cnt <= device->max_xor &&
is_dma_xor_aligned(device, offset, 0, len)) {
unsigned long dma_prep_flags = 0;
int i;
pr_debug("%s: (async) len: %zu\n", __func__, len);
if (submit->cb_fn)
dma_prep_flags |= DMA_PREP_INTERRUPT;
if (submit->flags & ASYNC_TX_FENCE)
dma_prep_flags |= DMA_PREP_FENCE;
for (i = 0; i < src_cnt; i++)
dma_src[i] = dma_map_page(device->dev, src_list[i],
offset, len, DMA_TO_DEVICE);
tx = device->device_prep_dma_xor_val(chan, dma_src, src_cnt,
len, result,
dma_prep_flags);
if (unlikely(!tx)) {
async_tx_quiesce(&submit->depend_tx);
while (!tx) {
dma_async_issue_pending(chan);
tx = device->device_prep_dma_xor_val(chan,
dma_src, src_cnt, len, result,
dma_prep_flags);
}
}
async_tx_submit(chan, tx, submit);
} else {
enum async_tx_flags flags_orig = submit->flags;
pr_debug("%s: (sync) len: %zu\n", __func__, len);
WARN_ONCE(device && src_cnt <= device->max_xor,
"%s: no space for dma address conversion\n",
__func__);
submit->flags |= ASYNC_TX_XOR_DROP_DST;
submit->flags &= ~ASYNC_TX_ACK;
tx = async_xor(dest, src_list, offset, src_cnt, len, submit);
async_tx_quiesce(&tx);
*result = !page_is_zero(dest, offset, len) << SUM_CHECK_P;
async_tx_sync_epilog(submit);
submit->flags = flags_orig;
}
return tx;
}
EXPORT_SYMBOL_GPL(async_xor_val);
MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api");
MODULE_LICENSE("GPL");