[deliverable/linux.git] / crypto / async_tx / async_xor.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.
 * 	This routine is marked __always_inline so it can be compiled away
 * 	when CONFIG_DMA_ENGINE=n
 */
static __always_inline struct dma_async_tx_descriptor *
do_async_xor(struct dma_device *device,
	struct dma_chan *chan, struct page *dest, struct page **src_list,
	unsigned int offset, unsigned int src_cnt, size_t len,
	enum async_tx_flags flags, struct dma_async_tx_descriptor *depend_tx,
	dma_async_tx_callback cb_fn, void *cb_param)
{
	dma_addr_t dma_dest;
	dma_addr_t *dma_src = (dma_addr_t *) src_list;
	struct dma_async_tx_descriptor *tx;
	int i;
	unsigned long dma_prep_flags = cb_fn ? DMA_PREP_INTERRUPT : 0;

	pr_debug("%s: len: %zu\n", __func__, len);

	dma_dest = dma_map_page(device->dev, dest, offset, len,
				DMA_FROM_DEVICE);

	for (i = 0; i < src_cnt; i++)
		dma_src[i] = dma_map_page(device->dev, src_list[i], offset,
					  len, DMA_TO_DEVICE);

	/* 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 = device->device_prep_dma_xor(chan, dma_dest, dma_src, src_cnt, len,
					 dma_prep_flags);
	if (!tx) {
		if (depend_tx)
			dma_wait_for_async_tx(depend_tx);

		while (!tx)
			tx = device->device_prep_dma_xor(chan, dma_dest,
							 dma_src, src_cnt, len,
							 dma_prep_flags);
	}

	async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);

	return tx;
}

static void
do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
	unsigned int src_cnt, size_t len, enum async_tx_flags flags,
	struct dma_async_tx_descriptor *depend_tx,
	dma_async_tx_callback cb_fn, void *cb_param)
{
	void *_dest;
	int i;

	pr_debug("%s: len: %zu\n", __func__, len);

	/* reuse the 'src_list' array to convert to buffer pointers */
	for (i = 0; i < src_cnt; i++)
		src_list[i] = (struct page *)
			(page_address(src_list[i]) + offset);

	/* set destination address */
	_dest = page_address(dest) + offset;

	if (flags & ASYNC_TX_XOR_ZERO_DST)
		memset(_dest, 0, len);

	xor_blocks(src_cnt, len, _dest,
		(void **) src_list);

	async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
}

/**
 * async_xor - attempt to xor a set of blocks with a dma engine.
 *	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.
 * @dest: destination page
 * @src_list: array of source pages (if the dest is also a source it must be
 *	at index zero).  The contents of this array may be overwritten.
 * @offset: offset in pages to start transaction
 * @src_cnt: number of source pages
 * @len: length in bytes
 * @flags: ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DEST,
 *	ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
 * @depend_tx: xor depends on the result of this transaction.
 * @cb_fn: function to call when the xor completes
 * @cb_param: parameter to pass to the callback routine
 */
struct dma_async_tx_descriptor *
async_xor(struct page *dest, struct page **src_list, unsigned int offset,
	int src_cnt, size_t len, enum async_tx_flags flags,
	struct dma_async_tx_descriptor *depend_tx,
	dma_async_tx_callback cb_fn, void *cb_param)
{
	struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_XOR,
						      &dest, 1, src_list,
						      src_cnt, len);
	struct dma_device *device = chan ? chan->device : NULL;
	struct dma_async_tx_descriptor *tx = NULL;
	dma_async_tx_callback _cb_fn;
	void *_cb_param;
	unsigned long local_flags;
	int xor_src_cnt;
	int i = 0, src_off = 0;

	BUG_ON(src_cnt <= 1);

	while (src_cnt) {
		local_flags = flags;
		if (device) { /* run the xor asynchronously */
			xor_src_cnt = min(src_cnt, device->max_xor);
			/* if we are submitting additional xors
			 * only set the callback on the last transaction
			 */
			if (src_cnt > xor_src_cnt) {
				local_flags &= ~ASYNC_TX_ACK;
				_cb_fn = NULL;
				_cb_param = NULL;
			} else {
				_cb_fn = cb_fn;
				_cb_param = cb_param;
			}

			tx = do_async_xor(device, chan, dest,
					  &src_list[src_off], offset,
					  xor_src_cnt, len, local_flags,
					  depend_tx, _cb_fn, _cb_param);
		} else { /* run the xor synchronously */
			/* in the sync case the dest is an implied source
			 * (assumes the dest is at the src_off index)
			 */
			if (flags & ASYNC_TX_XOR_DROP_DST) {
				src_cnt--;
				src_off++;
			}

			/* process up to 'MAX_XOR_BLOCKS' sources */
			xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);

			/* if we are submitting additional xors
			 * only set the callback on the last transaction
			 */
			if (src_cnt > xor_src_cnt) {
				local_flags &= ~ASYNC_TX_ACK;
				_cb_fn = NULL;
				_cb_param = NULL;
			} else {
				_cb_fn = cb_fn;
				_cb_param = cb_param;
			}

			/* wait for any prerequisite operations */
			if (depend_tx) {
				/* if ack is already set then we cannot be sure
				 * we are referring to the correct operation
				 */
				BUG_ON(async_tx_test_ack(depend_tx));
				if (dma_wait_for_async_tx(depend_tx) ==
					DMA_ERROR)
					panic("%s: DMA_ERROR waiting for "
						"depend_tx\n",
						__func__);
			}

			do_sync_xor(dest, &src_list[src_off], offset,
				xor_src_cnt, len, local_flags, depend_tx,
				_cb_fn, _cb_param);
		}

		/* the previous tx is hidden from the client,
		 * so ack it
		 */
		if (i && depend_tx)
			async_tx_ack(depend_tx);

		depend_tx = tx;

		if (src_cnt > xor_src_cnt) {
			/* drop completed sources */
			src_cnt -= xor_src_cnt;
			src_off += xor_src_cnt;

			/* unconditionally preserve the destination */
			flags &= ~ASYNC_TX_XOR_ZERO_DST;

			/* use the intermediate result a source, but remember
			 * it's dropped, because it's implied, in the sync case
			 */
			src_list[--src_off] = dest;
			src_cnt++;
			flags |= ASYNC_TX_XOR_DROP_DST;
		} else
			src_cnt = 0;
		i++;
	}

	return tx;
}
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);
}

/**
 * async_xor_zero_sum - 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.  The dest page must be listed as a source
 * 	at index zero.  The contents of this array may be overwritten.
 * @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
 * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
 * @depend_tx: xor depends on the result of this transaction.
 * @cb_fn: function to call when the xor completes
 * @cb_param: parameter to pass to the callback routine
 */
struct dma_async_tx_descriptor *
async_xor_zero_sum(struct page *dest, struct page **src_list,
	unsigned int offset, int src_cnt, size_t len,
	u32 *result, enum async_tx_flags flags,
	struct dma_async_tx_descriptor *depend_tx,
	dma_async_tx_callback cb_fn, void *cb_param)
{
	struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_ZERO_SUM,
						      &dest, 1, src_list,
						      src_cnt, len);
	struct dma_device *device = chan ? chan->device : NULL;
	struct dma_async_tx_descriptor *tx = NULL;

	BUG_ON(src_cnt <= 1);

	if (device && src_cnt <= device->max_xor) {
		dma_addr_t *dma_src = (dma_addr_t *) src_list;
		unsigned long dma_prep_flags = cb_fn ? DMA_PREP_INTERRUPT : 0;
		int i;

		pr_debug("%s: (async) len: %zu\n", __func__, len);

		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_zero_sum(chan, dma_src, src_cnt,
						      len, result,
						      dma_prep_flags);
		if (!tx) {
			if (depend_tx)
				dma_wait_for_async_tx(depend_tx);

			while (!tx)
				tx = device->device_prep_dma_zero_sum(chan,
					dma_src, src_cnt, len, result,
					dma_prep_flags);
		}

		async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
	} else {
		unsigned long xor_flags = flags;

		pr_debug("%s: (sync) len: %zu\n", __func__, len);

		xor_flags |= ASYNC_TX_XOR_DROP_DST;
		xor_flags &= ~ASYNC_TX_ACK;

		tx = async_xor(dest, src_list, offset, src_cnt, len, xor_flags,
			depend_tx, NULL, NULL);

		if (tx) {
			if (dma_wait_for_async_tx(tx) == DMA_ERROR)
				panic("%s: DMA_ERROR waiting for tx\n",
					__func__);
			async_tx_ack(tx);
		}

		*result = page_is_zero(dest, offset, len) ? 0 : 1;

		tx = NULL;

		async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
	}

	return tx;
}
EXPORT_SYMBOL_GPL(async_xor_zero_sum);

static int __init async_xor_init(void)
{
	#ifdef CONFIG_DMA_ENGINE
	/* To conserve stack space the input src_list (array of page pointers)
	 * is reused to hold the array of dma addresses passed to the driver.
	 * This conversion is only possible when dma_addr_t is less than the
	 * the size of a pointer.  HIGHMEM64G is known to violate this
	 * assumption.
	 */
	BUILD_BUG_ON(sizeof(dma_addr_t) > sizeof(struct page *));
	#endif

	return 0;
}

static void __exit async_xor_exit(void)
{
	do { } while (0);
}

module_init(async_xor_init);
module_exit(async_xor_exit);

MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api");
MODULE_LICENSE("GPL");
Commit	Line	Data
9bc89cd8 DW	1	/*
	2	* xor offload engine api
	3	*
	4	* Copyright © 2006, Intel Corporation.
	5	*
	6	* Dan Williams <dan.j.williams@intel.com>
	7	*
	8	* with architecture considerations by:
	9	* Neil Brown <neilb@suse.de>
	10	* Jeff Garzik <jeff@garzik.org>
	11	*
	12	* This program is free software; you can redistribute it and/or modify it
	13	* under the terms and conditions of the GNU General Public License,
	14	* version 2, as published by the Free Software Foundation.
	15	*
	16	* This program is distributed in the hope it will be useful, but WITHOUT
	17	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	18	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	19	* more details.
	20	*
	21	* You should have received a copy of the GNU General Public License along with
	22	* this program; if not, write to the Free Software Foundation, Inc.,
	23	* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
	24	*
	25	*/
	26	#include <linux/kernel.h>
	27	#include <linux/interrupt.h>
	28	#include <linux/mm.h>
	29	#include <linux/dma-mapping.h>
	30	#include <linux/raid/xor.h>
	31	#include <linux/async_tx.h>
	32
1367a3d3 DW	33	/* do_async_xor - dma map the pages and perform the xor with an engine.
	34	* This routine is marked __always_inline so it can be compiled away
	35	* when CONFIG_DMA_ENGINE=n
	36	*/
0036731c DW	37	static __always_inline struct dma_async_tx_descriptor *
0036731c DW	38	do_async_xor(struct dma_device *device,
9bc89cd8 DW	39	struct dma_chan chan, struct page dest, struct page **src_list,
	40	unsigned int offset, unsigned int src_cnt, size_t len,
	41	enum async_tx_flags flags, struct dma_async_tx_descriptor *depend_tx,
	42	dma_async_tx_callback cb_fn, void *cb_param)
	43	{
0036731c DW	44	dma_addr_t dma_dest;
	45	dma_addr_t dma_src = (dma_addr_t ) src_list;
	46	struct dma_async_tx_descriptor *tx;
9bc89cd8	47	int i;
d4c56f97	48	unsigned long dma_prep_flags = cb_fn ? DMA_PREP_INTERRUPT : 0;
9bc89cd8	49
3280ab3e	50	pr_debug("%s: len: %zu\n", __func__, len);
9bc89cd8	51
0036731c	52	dma_dest = dma_map_page(device->dev, dest, offset, len,
d909b347	53	DMA_FROM_DEVICE);
9bc89cd8	54
0036731c DW	55	for (i = 0; i < src_cnt; i++)
	56	dma_src[i] = dma_map_page(device->dev, src_list[i], offset,
	57	len, DMA_TO_DEVICE);
	58
	59	/* Since we have clobbered the src_list we are committed
	60	* to doing this asynchronously. Drivers force forward progress
	61	* in case they can not provide a descriptor
	62	*/
	63	tx = device->device_prep_dma_xor(chan, dma_dest, dma_src, src_cnt, len,
d4c56f97	64	dma_prep_flags);
0036731c DW	65	if (!tx) {
	66	if (depend_tx)
	67	dma_wait_for_async_tx(depend_tx);
	68
	69	while (!tx)
	70	tx = device->device_prep_dma_xor(chan, dma_dest,
	71	dma_src, src_cnt, len,
d4c56f97	72	dma_prep_flags);
9bc89cd8 DW	73	}
	74
	75	async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
0036731c DW	76
0036731c DW	77	return tx;
9bc89cd8 DW	78	}
	79
	80	static void
	81	do_sync_xor(struct page dest, struct page *src_list, unsigned int offset,
	82	unsigned int src_cnt, size_t len, enum async_tx_flags flags,
	83	struct dma_async_tx_descriptor *depend_tx,
	84	dma_async_tx_callback cb_fn, void *cb_param)
	85	{
	86	void *_dest;
	87	int i;
	88
3280ab3e	89	pr_debug("%s: len: %zu\n", __func__, len);
9bc89cd8 DW	90
	91	/* reuse the 'src_list' array to convert to buffer pointers */
	92	for (i = 0; i < src_cnt; i++)
	93	src_list[i] = (struct page *)
	94	(page_address(src_list[i]) + offset);
	95
	96	/* set destination address */
	97	_dest = page_address(dest) + offset;
	98
	99	if (flags & ASYNC_TX_XOR_ZERO_DST)
	100	memset(_dest, 0, len);
	101
	102	xor_blocks(src_cnt, len, _dest,
	103	(void **) src_list);
	104
	105	async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
	106	}
	107
	108	/**
	109	* async_xor - attempt to xor a set of blocks with a dma engine.
	110	* xor_blocks always uses the dest as a source so the ASYNC_TX_XOR_ZERO_DST
	111	* flag must be set to not include dest data in the calculation. The
	112	* assumption with dma eninges is that they only use the destination
	113	* buffer as a source when it is explicity specified in the source list.
	114	* @dest: destination page
	115	* @src_list: array of source pages (if the dest is also a source it must be
	116	* at index zero). The contents of this array may be overwritten.
	117	* @offset: offset in pages to start transaction
	118	* @src_cnt: number of source pages
	119	* @len: length in bytes
	120	* @flags: ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DEST,
d909b347	121	* ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
9bc89cd8 DW	122	* @depend_tx: xor depends on the result of this transaction.
	123	* @cb_fn: function to call when the xor completes
	124	* @cb_param: parameter to pass to the callback routine
	125	*/
	126	struct dma_async_tx_descriptor *
	127	async_xor(struct page dest, struct page *src_list, unsigned int offset,
	128	int src_cnt, size_t len, enum async_tx_flags flags,
	129	struct dma_async_tx_descriptor *depend_tx,
	130	dma_async_tx_callback cb_fn, void *cb_param)
	131	{
47437b2c DW	132	struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_XOR,
	133	&dest, 1, src_list,
	134	src_cnt, len);
9bc89cd8 DW	135	struct dma_device *device = chan ? chan->device : NULL;
	136	struct dma_async_tx_descriptor *tx = NULL;
	137	dma_async_tx_callback _cb_fn;
	138	void *_cb_param;
	139	unsigned long local_flags;
	140	int xor_src_cnt;
0036731c	141	int i = 0, src_off = 0;
9bc89cd8 DW	142
	143	BUG_ON(src_cnt <= 1);
	144
	145	while (src_cnt) {
	146	local_flags = flags;
	147	if (device) { /* run the xor asynchronously */
	148	xor_src_cnt = min(src_cnt, device->max_xor);
	149	/* if we are submitting additional xors
	150	* only set the callback on the last transaction
	151	*/
	152	if (src_cnt > xor_src_cnt) {
	153	local_flags &= ~ASYNC_TX_ACK;
	154	_cb_fn = NULL;
	155	_cb_param = NULL;
	156	} else {
	157	_cb_fn = cb_fn;
	158	_cb_param = cb_param;
	159	}
	160
0036731c DW	161	tx = do_async_xor(device, chan, dest,
	162	&src_list[src_off], offset,
	163	xor_src_cnt, len, local_flags,
	164	depend_tx, _cb_fn, _cb_param);
9bc89cd8	165	} else { /* run the xor synchronously */
9bc89cd8 DW	166	/* in the sync case the dest is an implied source
	167	* (assumes the dest is at the src_off index)
	168	*/
	169	if (flags & ASYNC_TX_XOR_DROP_DST) {
	170	src_cnt--;
	171	src_off++;
	172	}
	173
	174	/* process up to 'MAX_XOR_BLOCKS' sources */
	175	xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
	176
	177	/* if we are submitting additional xors
	178	* only set the callback on the last transaction
	179	*/
	180	if (src_cnt > xor_src_cnt) {
	181	local_flags &= ~ASYNC_TX_ACK;
	182	_cb_fn = NULL;
	183	_cb_param = NULL;
	184	} else {
	185	_cb_fn = cb_fn;
	186	_cb_param = cb_param;
	187	}
	188
	189	/* wait for any prerequisite operations */
	190	if (depend_tx) {
	191	/* if ack is already set then we cannot be sure
	192	* we are referring to the correct operation
	193	*/
636bdeaa	194	BUG_ON(async_tx_test_ack(depend_tx));
9bc89cd8 DW	195	if (dma_wait_for_async_tx(depend_tx) ==
	196	DMA_ERROR)
	197	panic("%s: DMA_ERROR waiting for "
	198	"depend_tx\n",
3280ab3e	199	__func__);
9bc89cd8 DW	200	}
	201
	202	do_sync_xor(dest, &src_list[src_off], offset,
	203	xor_src_cnt, len, local_flags, depend_tx,
	204	_cb_fn, _cb_param);
	205	}
	206
	207	/* the previous tx is hidden from the client,
	208	* so ack it
	209	*/
	210	if (i && depend_tx)
	211	async_tx_ack(depend_tx);
	212
	213	depend_tx = tx;
	214
	215	if (src_cnt > xor_src_cnt) {
	216	/* drop completed sources */
	217	src_cnt -= xor_src_cnt;
	218	src_off += xor_src_cnt;
	219
	220	/* unconditionally preserve the destination */
	221	flags &= ~ASYNC_TX_XOR_ZERO_DST;
	222
	223	/* use the intermediate result a source, but remember
	224	* it's dropped, because it's implied, in the sync case
	225	*/
	226	src_list[--src_off] = dest;
	227	src_cnt++;
	228	flags \|= ASYNC_TX_XOR_DROP_DST;
	229	} else
	230	src_cnt = 0;
	231	i++;
	232	}
	233
	234	return tx;
	235	}
	236	EXPORT_SYMBOL_GPL(async_xor);
	237
	238	static int page_is_zero(struct page *p, unsigned int offset, size_t len)
	239	{
	240	char *a = page_address(p) + offset;
	241	return (((u32 ) a) == 0 &&
	242	memcmp(a, a + 4, len - 4) == 0);
	243	}
	244
	245	/**
	246	* async_xor_zero_sum - attempt a xor parity check with a dma engine.
	247	* @dest: destination page used if the xor is performed synchronously
	248	* @src_list: array of source pages. The dest page must be listed as a source
	249	* at index zero. The contents of this array may be overwritten.
	250	* @offset: offset in pages to start transaction
	251	* @src_cnt: number of source pages
	252	* @len: length in bytes
	253	* @result: 0 if sum == 0 else non-zero
d909b347	254	* @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
9bc89cd8 DW	255	* @depend_tx: xor depends on the result of this transaction.
	256	* @cb_fn: function to call when the xor completes
	257	* @cb_param: parameter to pass to the callback routine
	258	*/
	259	struct dma_async_tx_descriptor *
	260	async_xor_zero_sum(struct page dest, struct page *src_list,
	261	unsigned int offset, int src_cnt, size_t len,
	262	u32 *result, enum async_tx_flags flags,
	263	struct dma_async_tx_descriptor *depend_tx,
	264	dma_async_tx_callback cb_fn, void *cb_param)
	265	{
47437b2c DW	266	struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_ZERO_SUM,
	267	&dest, 1, src_list,
	268	src_cnt, len);
9bc89cd8	269	struct dma_device *device = chan ? chan->device : NULL;
0036731c	270	struct dma_async_tx_descriptor *tx = NULL;
9bc89cd8 DW	271
	272	BUG_ON(src_cnt <= 1);
	273
8d8002f6	274	if (device && src_cnt <= device->max_xor) {
0036731c	275	dma_addr_t dma_src = (dma_addr_t ) src_list;
d4c56f97	276	unsigned long dma_prep_flags = cb_fn ? DMA_PREP_INTERRUPT : 0;
0036731c	277	int i;
9bc89cd8	278
3280ab3e	279	pr_debug("%s: (async) len: %zu\n", __func__, len);
9bc89cd8	280
0036731c DW	281	for (i = 0; i < src_cnt; i++)
	282	dma_src[i] = dma_map_page(device->dev, src_list[i],
	283	offset, len, DMA_TO_DEVICE);
	284
	285	tx = device->device_prep_dma_zero_sum(chan, dma_src, src_cnt,
	286	len, result,
d4c56f97	287	dma_prep_flags);
0036731c DW	288	if (!tx) {
	289	if (depend_tx)
	290	dma_wait_for_async_tx(depend_tx);
	291
	292	while (!tx)
	293	tx = device->device_prep_dma_zero_sum(chan,
	294	dma_src, src_cnt, len, result,
d4c56f97	295	dma_prep_flags);
9bc89cd8 DW	296	}
	297
	298	async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
	299	} else {
	300	unsigned long xor_flags = flags;
	301
3280ab3e	302	pr_debug("%s: (sync) len: %zu\n", __func__, len);
9bc89cd8 DW	303
	304	xor_flags \|= ASYNC_TX_XOR_DROP_DST;
	305	xor_flags &= ~ASYNC_TX_ACK;
	306
	307	tx = async_xor(dest, src_list, offset, src_cnt, len, xor_flags,
	308	depend_tx, NULL, NULL);
	309
	310	if (tx) {
	311	if (dma_wait_for_async_tx(tx) == DMA_ERROR)
	312	panic("%s: DMA_ERROR waiting for tx\n",
3280ab3e	313	__func__);
9bc89cd8 DW	314	async_tx_ack(tx);
	315	}
	316
	317	*result = page_is_zero(dest, offset, len) ? 0 : 1;
	318
	319	tx = NULL;
	320
	321	async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
	322	}
	323
	324	return tx;
	325	}
	326	EXPORT_SYMBOL_GPL(async_xor_zero_sum);
	327
	328	static int __init async_xor_init(void)
	329	{
0036731c DW	330	#ifdef CONFIG_DMA_ENGINE
	331	/* To conserve stack space the input src_list (array of page pointers)
	332	* is reused to hold the array of dma addresses passed to the driver.
	333	* This conversion is only possible when dma_addr_t is less than the
	334	* the size of a pointer. HIGHMEM64G is known to violate this
	335	* assumption.
	336	*/
	337	BUILD_BUG_ON(sizeof(dma_addr_t) > sizeof(struct page *));
	338	#endif
	339
9bc89cd8 DW	340	return 0;
	341	}
	342
	343	static void __exit async_xor_exit(void)
	344	{
	345	do { } while (0);
	346	}
	347
	348	module_init(async_xor_init);
	349	module_exit(async_xor_exit);
	350
	351	MODULE_AUTHOR("Intel Corporation");
	352	MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api");
	353	MODULE_LICENSE("GPL");