339 lines
9.8 KiB
C
339 lines
9.8 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/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 preceeding 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");
|