[net-next-2.6.git] / crypto / async_tx / async_pq.c

/*
 * Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com>
 * Copyright(c) 2009 Intel Corporation
 *
 * 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., 59
 * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The full GNU General Public License is included in this distribution in the
 * file called COPYING.
 */
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/raid/pq.h>
#include <linux/async_tx.h>
#include <linux/gfp.h>

/**
 * pq_scribble_page - space to hold throwaway P or Q buffer for
 * synchronous gen_syndrome
 */
static struct page *pq_scribble_page;

/* the struct page *blocks[] parameter passed to async_gen_syndrome()
 * and async_syndrome_val() contains the 'P' destination address at
 * blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
 *
 * note: these are macros as they are used as lvalues
 */
#define P(b, d) (b[d-2])
#define Q(b, d) (b[d-1])

/**
 * do_async_gen_syndrome - asynchronously calculate P and/or Q
 */
static __async_inline struct dma_async_tx_descriptor *
do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks,
		      const unsigned char *scfs, unsigned int offset, int disks,
		      size_t len, dma_addr_t *dma_src,
		      struct async_submit_ctl *submit)
{
	struct dma_async_tx_descriptor *tx = NULL;
	struct dma_device *dma = chan->device;
	enum dma_ctrl_flags dma_flags = 0;
	enum async_tx_flags flags_orig = submit->flags;
	dma_async_tx_callback cb_fn_orig = submit->cb_fn;
	dma_async_tx_callback cb_param_orig = submit->cb_param;
	int src_cnt = disks - 2;
	unsigned char coefs[src_cnt];
	unsigned short pq_src_cnt;
	dma_addr_t dma_dest[2];
	int src_off = 0;
	int idx;
	int i;

	/* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */
	if (P(blocks, disks))
		dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset,
					   len, DMA_BIDIRECTIONAL);
	else
		dma_flags |= DMA_PREP_PQ_DISABLE_P;
	if (Q(blocks, disks))
		dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset,
					   len, DMA_BIDIRECTIONAL);
	else
		dma_flags |= DMA_PREP_PQ_DISABLE_Q;

	/* convert source addresses being careful to collapse 'empty'
	 * sources and update the coefficients accordingly
	 */
	for (i = 0, idx = 0; i < src_cnt; i++) {
		if (blocks[i] == NULL)
			continue;
		dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len,
					    DMA_TO_DEVICE);
		coefs[idx] = scfs[i];
		idx++;
	}
	src_cnt = idx;

	while (src_cnt > 0) {
		submit->flags = flags_orig;
		pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
		/* if we are submitting additional pqs, leave the chain open,
		 * clear the callback parameters, and leave the destination
		 * buffers mapped
		 */
		if (src_cnt > pq_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 {
			dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP;
			submit->cb_fn = cb_fn_orig;
			submit->cb_param = cb_param_orig;
			if (cb_fn_orig)
				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
		 */
		for (;;) {
			tx = dma->device_prep_dma_pq(chan, dma_dest,
						     &dma_src[src_off],
						     pq_src_cnt,
						     &coefs[src_off], len,
						     dma_flags);
			if (likely(tx))
				break;
			async_tx_quiesce(&submit->depend_tx);
			dma_async_issue_pending(chan);
		}

		async_tx_submit(chan, tx, submit);
		submit->depend_tx = tx;

		/* drop completed sources */
		src_cnt -= pq_src_cnt;
		src_off += pq_src_cnt;

		dma_flags |= DMA_PREP_CONTINUE;
	}

	return tx;
}

/**
 * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome
 */
static void
do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
		     size_t len, struct async_submit_ctl *submit)
{
	void **srcs;
	int i;

	if (submit->scribble)
		srcs = submit->scribble;
	else
		srcs = (void **) blocks;

	for (i = 0; i < disks; i++) {
		if (blocks[i] == NULL) {
			BUG_ON(i > disks - 3); /* P or Q can't be zero */
			srcs[i] = (void*)raid6_empty_zero_page;
		} else
			srcs[i] = page_address(blocks[i]) + offset;
	}
	raid6_call.gen_syndrome(disks, len, srcs);
	async_tx_sync_epilog(submit);
}

/**
 * async_gen_syndrome - asynchronously calculate a raid6 syndrome
 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
 * @offset: common offset into each block (src and dest) to start transaction
 * @disks: number of blocks (including missing P or Q, see below)
 * @len: length of operation in bytes
 * @submit: submission/completion modifiers
 *
 * General note: This routine assumes a field of GF(2^8) with a
 * primitive polynomial of 0x11d and a generator of {02}.
 *
 * 'disks' note: callers can optionally omit either P or Q (but not
 * both) from the calculation by setting blocks[disks-2] or
 * blocks[disks-1] to NULL.  When P or Q is omitted 'len' must be <=
 * PAGE_SIZE as a temporary buffer of this size is used in the
 * synchronous path.  'disks' always accounts for both destination
 * buffers.  If any source buffers (blocks[i] where i < disks - 2) are
 * set to NULL those buffers will be replaced with the raid6_zero_page
 * in the synchronous path and omitted in the hardware-asynchronous
 * path.
 *
 * 'blocks' note: if submit->scribble is NULL then the contents of
 * 'blocks' may be overwritten to perform address conversions
 * (dma_map_page() or page_address()).
 */
struct dma_async_tx_descriptor *
async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
		   size_t len, struct async_submit_ctl *submit)
{
	int src_cnt = disks - 2;
	struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
						      &P(blocks, disks), 2,
						      blocks, src_cnt, len);
	struct dma_device *device = chan ? chan->device : NULL;
	dma_addr_t *dma_src = NULL;

	BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks)));

	if (submit->scribble)
		dma_src = submit->scribble;
	else if (sizeof(dma_addr_t) <= sizeof(struct page *))
		dma_src = (dma_addr_t *) blocks;

	if (dma_src && device &&
	    (src_cnt <= dma_maxpq(device, 0) ||
	     dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
	    is_dma_pq_aligned(device, offset, 0, len)) {
		/* run the p+q asynchronously */
		pr_debug("%s: (async) disks: %d len: %zu\n",
			 __func__, disks, len);
		return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset,
					     disks, len, dma_src, submit);
	}

	/* run the pq synchronously */
	pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);

	/* wait for any prerequisite operations */
	async_tx_quiesce(&submit->depend_tx);

	if (!P(blocks, disks)) {
		P(blocks, disks) = pq_scribble_page;
		BUG_ON(len + offset > PAGE_SIZE);
	}
	if (!Q(blocks, disks)) {
		Q(blocks, disks) = pq_scribble_page;
		BUG_ON(len + offset > PAGE_SIZE);
	}
	do_sync_gen_syndrome(blocks, offset, disks, len, submit);

	return NULL;
}
EXPORT_SYMBOL_GPL(async_gen_syndrome);

static inline struct dma_chan *
pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len)
{
	#ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
	return NULL;
	#endif
	return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0,  blocks,
				     disks, len);
}

/**
 * async_syndrome_val - asynchronously validate a raid6 syndrome
 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
 * @offset: common offset into each block (src and dest) to start transaction
 * @disks: number of blocks (including missing P or Q, see below)
 * @len: length of operation in bytes
 * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set
 * @spare: temporary result buffer for the synchronous case
 * @submit: submission / completion modifiers
 *
 * The same notes from async_gen_syndrome apply to the 'blocks',
 * and 'disks' parameters of this routine.  The synchronous path
 * requires a temporary result buffer and submit->scribble to be
 * specified.
 */
struct dma_async_tx_descriptor *
async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
		   size_t len, enum sum_check_flags *pqres, struct page *spare,
		   struct async_submit_ctl *submit)
{
	struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
	struct dma_device *device = chan ? chan->device : NULL;
	struct dma_async_tx_descriptor *tx;
	unsigned char coefs[disks-2];
	enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
	dma_addr_t *dma_src = NULL;
	int src_cnt = 0;

	BUG_ON(disks < 4);

	if (submit->scribble)
		dma_src = submit->scribble;
	else if (sizeof(dma_addr_t) <= sizeof(struct page *))
		dma_src = (dma_addr_t *) blocks;

	if (dma_src && device && disks <= dma_maxpq(device, 0) &&
	    is_dma_pq_aligned(device, offset, 0, len)) {
		struct device *dev = device->dev;
		dma_addr_t *pq = &dma_src[disks-2];
		int i;

		pr_debug("%s: (async) disks: %d len: %zu\n",
			 __func__, disks, len);
		if (!P(blocks, disks))
			dma_flags |= DMA_PREP_PQ_DISABLE_P;
		else
			pq[0] = dma_map_page(dev, P(blocks, disks),
					     offset, len,
					     DMA_TO_DEVICE);
		if (!Q(blocks, disks))
			dma_flags |= DMA_PREP_PQ_DISABLE_Q;
		else
			pq[1] = dma_map_page(dev, Q(blocks, disks),
					     offset, len,
					     DMA_TO_DEVICE);

		if (submit->flags & ASYNC_TX_FENCE)
			dma_flags |= DMA_PREP_FENCE;
		for (i = 0; i < disks-2; i++)
			if (likely(blocks[i])) {
				dma_src[src_cnt] = dma_map_page(dev, blocks[i],
								offset, len,
								DMA_TO_DEVICE);
				coefs[src_cnt] = raid6_gfexp[i];
				src_cnt++;
			}

		for (;;) {
			tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
							    src_cnt,
							    coefs,
							    len, pqres,
							    dma_flags);
			if (likely(tx))
				break;
			async_tx_quiesce(&submit->depend_tx);
			dma_async_issue_pending(chan);
		}
		async_tx_submit(chan, tx, submit);

		return tx;
	} else {
		struct page *p_src = P(blocks, disks);
		struct page *q_src = Q(blocks, disks);
		enum async_tx_flags flags_orig = submit->flags;
		dma_async_tx_callback cb_fn_orig = submit->cb_fn;
		void *scribble = submit->scribble;
		void *cb_param_orig = submit->cb_param;
		void *p, *q, *s;

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

		/* caller must provide a temporary result buffer and
		 * allow the input parameters to be preserved
		 */
		BUG_ON(!spare || !scribble);

		/* wait for any prerequisite operations */
		async_tx_quiesce(&submit->depend_tx);

		/* recompute p and/or q into the temporary buffer and then
		 * check to see the result matches the current value
		 */
		tx = NULL;
		*pqres = 0;
		if (p_src) {
			init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
					  NULL, NULL, scribble);
			tx = async_xor(spare, blocks, offset, disks-2, len, submit);
			async_tx_quiesce(&tx);
			p = page_address(p_src) + offset;
			s = page_address(spare) + offset;
			*pqres |= !!memcmp(p, s, len) << SUM_CHECK_P;
		}

		if (q_src) {
			P(blocks, disks) = NULL;
			Q(blocks, disks) = spare;
			init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
			tx = async_gen_syndrome(blocks, offset, disks, len, submit);
			async_tx_quiesce(&tx);
			q = page_address(q_src) + offset;
			s = page_address(spare) + offset;
			*pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q;
		}

		/* restore P, Q and submit */
		P(blocks, disks) = p_src;
		Q(blocks, disks) = q_src;

		submit->cb_fn = cb_fn_orig;
		submit->cb_param = cb_param_orig;
		submit->flags = flags_orig;
		async_tx_sync_epilog(submit);

		return NULL;
	}
}
EXPORT_SYMBOL_GPL(async_syndrome_val);

static int __init async_pq_init(void)
{
	pq_scribble_page = alloc_page(GFP_KERNEL);

	if (pq_scribble_page)
		return 0;

	pr_err("%s: failed to allocate required spare page\n", __func__);

	return -ENOMEM;
}

static void __exit async_pq_exit(void)
{
	put_page(pq_scribble_page);
}

module_init(async_pq_init);
module_exit(async_pq_exit);

MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
MODULE_LICENSE("GPL");
Commit	Line	Data
b2f46fd8 DW	1	/*
	2	* Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com>
	3	* Copyright(c) 2009 Intel Corporation
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License as published by the Free
	7	* Software Foundation; either version 2 of the License, or (at your option)
	8	* any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful, but WITHOUT
	11	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	* more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along with
	16	* this program; if not, write to the Free Software Foundation, Inc., 59
	17	* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	18	*
	19	* The full GNU General Public License is included in this distribution in the
	20	* file called COPYING.
	21	*/
	22	#include <linux/kernel.h>
	23	#include <linux/interrupt.h>
	24	#include <linux/dma-mapping.h>
	25	#include <linux/raid/pq.h>
	26	#include <linux/async_tx.h>
5a0e3ad6	27	#include <linux/gfp.h>
b2f46fd8 DW	28
b2f46fd8 DW	29	/**
030b0772 DW	30	* pq_scribble_page - space to hold throwaway P or Q buffer for
030b0772 DW	31	* synchronous gen_syndrome
b2f46fd8	32	*/
030b0772	33	static struct page *pq_scribble_page;
b2f46fd8	34
b2f46fd8 DW	35	/* the struct page *blocks[] parameter passed to async_gen_syndrome()
	36	* and async_syndrome_val() contains the 'P' destination address at
	37	* blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
	38	*
	39	* note: these are macros as they are used as lvalues
	40	*/
	41	#define P(b, d) (b[d-2])
	42	#define Q(b, d) (b[d-1])
	43
	44	/**
	45	* do_async_gen_syndrome - asynchronously calculate P and/or Q
	46	*/
	47	static __async_inline struct dma_async_tx_descriptor *
	48	do_async_gen_syndrome(struct dma_chan chan, struct page *blocks,
	49	const unsigned char *scfs, unsigned int offset, int disks,
	50	size_t len, dma_addr_t *dma_src,
	51	struct async_submit_ctl *submit)
	52	{
	53	struct dma_async_tx_descriptor *tx = NULL;
	54	struct dma_device *dma = chan->device;
	55	enum dma_ctrl_flags dma_flags = 0;
	56	enum async_tx_flags flags_orig = submit->flags;
	57	dma_async_tx_callback cb_fn_orig = submit->cb_fn;
	58	dma_async_tx_callback cb_param_orig = submit->cb_param;
	59	int src_cnt = disks - 2;
	60	unsigned char coefs[src_cnt];
	61	unsigned short pq_src_cnt;
	62	dma_addr_t dma_dest[2];
	63	int src_off = 0;
	64	int idx;
	65	int i;
	66
	67	/* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */
	68	if (P(blocks, disks))
	69	dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset,
	70	len, DMA_BIDIRECTIONAL);
	71	else
	72	dma_flags \|= DMA_PREP_PQ_DISABLE_P;
	73	if (Q(blocks, disks))
	74	dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset,
	75	len, DMA_BIDIRECTIONAL);
	76	else
	77	dma_flags \|= DMA_PREP_PQ_DISABLE_Q;
	78
	79	/* convert source addresses being careful to collapse 'empty'
	80	* sources and update the coefficients accordingly
	81	*/
	82	for (i = 0, idx = 0; i < src_cnt; i++) {
5dd33c9a	83	if (blocks[i] == NULL)
b2f46fd8 DW	84	continue;
	85	dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len,
	86	DMA_TO_DEVICE);
	87	coefs[idx] = scfs[i];
	88	idx++;
	89	}
	90	src_cnt = idx;
	91
	92	while (src_cnt > 0) {
	93	submit->flags = flags_orig;
	94	pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
	95	/* if we are submitting additional pqs, leave the chain open,
	96	* clear the callback parameters, and leave the destination
	97	* buffers mapped
	98	*/
	99	if (src_cnt > pq_src_cnt) {
	100	submit->flags &= ~ASYNC_TX_ACK;
0403e382	101	submit->flags \|= ASYNC_TX_FENCE;
b2f46fd8 DW	102	dma_flags \|= DMA_COMPL_SKIP_DEST_UNMAP;
	103	submit->cb_fn = NULL;
	104	submit->cb_param = NULL;
	105	} else {
	106	dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP;
	107	submit->cb_fn = cb_fn_orig;
	108	submit->cb_param = cb_param_orig;
	109	if (cb_fn_orig)
	110	dma_flags \|= DMA_PREP_INTERRUPT;
	111	}
0403e382 DW	112	if (submit->flags & ASYNC_TX_FENCE)
0403e382 DW	113	dma_flags \|= DMA_PREP_FENCE;
b2f46fd8 DW	114
	115	/* Since we have clobbered the src_list we are committed
	116	* to doing this asynchronously. Drivers force forward
	117	* progress in case they can not provide a descriptor
	118	*/
	119	for (;;) {
	120	tx = dma->device_prep_dma_pq(chan, dma_dest,
	121	&dma_src[src_off],
	122	pq_src_cnt,
	123	&coefs[src_off], len,
	124	dma_flags);
	125	if (likely(tx))
	126	break;
	127	async_tx_quiesce(&submit->depend_tx);
	128	dma_async_issue_pending(chan);
	129	}
	130
	131	async_tx_submit(chan, tx, submit);
	132	submit->depend_tx = tx;
	133
	134	/* drop completed sources */
	135	src_cnt -= pq_src_cnt;
	136	src_off += pq_src_cnt;
	137
	138	dma_flags \|= DMA_PREP_CONTINUE;
	139	}
	140
	141	return tx;
	142	}
	143
	144	/**
	145	* do_sync_gen_syndrome - synchronously calculate a raid6 syndrome
	146	*/
	147	static void
	148	do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
	149	size_t len, struct async_submit_ctl *submit)
	150	{
	151	void **srcs;
	152	int i;
	153
	154	if (submit->scribble)
	155	srcs = submit->scribble;
	156	else
	157	srcs = (void **) blocks;
	158
	159	for (i = 0; i < disks; i++) {
5dd33c9a	160	if (blocks[i] == NULL) {
b2f46fd8	161	BUG_ON(i > disks - 3); /* P or Q can't be zero */
5dd33c9a	162	srcs[i] = (void*)raid6_empty_zero_page;
b2f46fd8 DW	163	} else
	164	srcs[i] = page_address(blocks[i]) + offset;
	165	}
	166	raid6_call.gen_syndrome(disks, len, srcs);
	167	async_tx_sync_epilog(submit);
	168	}
	169
	170	/**
	171	* async_gen_syndrome - asynchronously calculate a raid6 syndrome
	172	* @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
	173	* @offset: common offset into each block (src and dest) to start transaction
	174	* @disks: number of blocks (including missing P or Q, see below)
	175	* @len: length of operation in bytes
	176	* @submit: submission/completion modifiers
	177	*
	178	* General note: This routine assumes a field of GF(2^8) with a
	179	* primitive polynomial of 0x11d and a generator of {02}.
	180	*
	181	* 'disks' note: callers can optionally omit either P or Q (but not
	182	* both) from the calculation by setting blocks[disks-2] or
	183	* blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <=
	184	* PAGE_SIZE as a temporary buffer of this size is used in the
	185	* synchronous path. 'disks' always accounts for both destination
5676470f DW	186	* buffers. If any source buffers (blocks[i] where i < disks - 2) are
	187	* set to NULL those buffers will be replaced with the raid6_zero_page
	188	* in the synchronous path and omitted in the hardware-asynchronous
	189	* path.
b2f46fd8 DW	190	*
b2f46fd8 DW	191	* 'blocks' note: if submit->scribble is NULL then the contents of
5676470f DW	192	* 'blocks' may be overwritten to perform address conversions
5676470f DW	193	* (dma_map_page() or page_address()).
b2f46fd8 DW	194	*/
	195	struct dma_async_tx_descriptor *
	196	async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
	197	size_t len, struct async_submit_ctl *submit)
	198	{
	199	int src_cnt = disks - 2;
	200	struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
	201	&P(blocks, disks), 2,
	202	blocks, src_cnt, len);
	203	struct dma_device *device = chan ? chan->device : NULL;
	204	dma_addr_t *dma_src = NULL;
	205
	206	BUG_ON(disks > 255 \|\| !(P(blocks, disks) \|\| Q(blocks, disks)));
	207
	208	if (submit->scribble)
	209	dma_src = submit->scribble;
	210	else if (sizeof(dma_addr_t) <= sizeof(struct page *))
	211	dma_src = (dma_addr_t *) blocks;
	212
	213	if (dma_src && device &&
	214	(src_cnt <= dma_maxpq(device, 0) \|\|
83544ae9 DW	215	dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
83544ae9 DW	216	is_dma_pq_aligned(device, offset, 0, len)) {
b2f46fd8 DW	217	/* run the p+q asynchronously */
	218	pr_debug("%s: (async) disks: %d len: %zu\n",
	219	__func__, disks, len);
	220	return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset,
	221	disks, len, dma_src, submit);
	222	}
	223
	224	/* run the pq synchronously */
	225	pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
	226
	227	/* wait for any prerequisite operations */
	228	async_tx_quiesce(&submit->depend_tx);
	229
	230	if (!P(blocks, disks)) {
030b0772	231	P(blocks, disks) = pq_scribble_page;
b2f46fd8 DW	232	BUG_ON(len + offset > PAGE_SIZE);
	233	}
	234	if (!Q(blocks, disks)) {
030b0772	235	Q(blocks, disks) = pq_scribble_page;
b2f46fd8 DW	236	BUG_ON(len + offset > PAGE_SIZE);
	237	}
	238	do_sync_gen_syndrome(blocks, offset, disks, len, submit);
	239
	240	return NULL;
	241	}
	242	EXPORT_SYMBOL_GPL(async_gen_syndrome);
	243
7b3cc2b1 DW	244	static inline struct dma_chan *
	245	pq_val_chan(struct async_submit_ctl submit, struct page *blocks, int disks, size_t len)
	246	{
	247	#ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
	248	return NULL;
	249	#endif
	250	return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks,
	251	disks, len);
	252	}
	253
b2f46fd8 DW	254	/**
	255	* async_syndrome_val - asynchronously validate a raid6 syndrome
	256	* @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
	257	* @offset: common offset into each block (src and dest) to start transaction
	258	* @disks: number of blocks (including missing P or Q, see below)
	259	* @len: length of operation in bytes
	260	* @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set
	261	* @spare: temporary result buffer for the synchronous case
	262	* @submit: submission / completion modifiers
	263	*
	264	* The same notes from async_gen_syndrome apply to the 'blocks',
	265	* and 'disks' parameters of this routine. The synchronous path
	266	* requires a temporary result buffer and submit->scribble to be
	267	* specified.
	268	*/
	269	struct dma_async_tx_descriptor *
	270	async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
	271	size_t len, enum sum_check_flags pqres, struct page spare,
	272	struct async_submit_ctl *submit)
	273	{
7b3cc2b1	274	struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
b2f46fd8 DW	275	struct dma_device *device = chan ? chan->device : NULL;
b2f46fd8 DW	276	struct dma_async_tx_descriptor *tx;
b2141e69	277	unsigned char coefs[disks-2];
b2f46fd8 DW	278	enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
b2f46fd8 DW	279	dma_addr_t *dma_src = NULL;
b2141e69	280	int src_cnt = 0;
b2f46fd8 DW	281
	282	BUG_ON(disks < 4);
	283
	284	if (submit->scribble)
	285	dma_src = submit->scribble;
	286	else if (sizeof(dma_addr_t) <= sizeof(struct page *))
	287	dma_src = (dma_addr_t *) blocks;
	288
83544ae9 DW	289	if (dma_src && device && disks <= dma_maxpq(device, 0) &&
83544ae9 DW	290	is_dma_pq_aligned(device, offset, 0, len)) {
b2f46fd8 DW	291	struct device *dev = device->dev;
	292	dma_addr_t *pq = &dma_src[disks-2];
	293	int i;
	294
	295	pr_debug("%s: (async) disks: %d len: %zu\n",
	296	__func__, disks, len);
	297	if (!P(blocks, disks))
	298	dma_flags \|= DMA_PREP_PQ_DISABLE_P;
b2141e69	299	else
5676470f	300	pq[0] = dma_map_page(dev, P(blocks, disks),
b2141e69 N	301	offset, len,
b2141e69 N	302	DMA_TO_DEVICE);
b2f46fd8 DW	303	if (!Q(blocks, disks))
b2f46fd8 DW	304	dma_flags \|= DMA_PREP_PQ_DISABLE_Q;
b2141e69	305	else
5676470f	306	pq[1] = dma_map_page(dev, Q(blocks, disks),
b2141e69 N	307	offset, len,
	308	DMA_TO_DEVICE);
	309
0403e382 DW	310	if (submit->flags & ASYNC_TX_FENCE)
0403e382 DW	311	dma_flags \|= DMA_PREP_FENCE;
b2141e69 N	312	for (i = 0; i < disks-2; i++)
	313	if (likely(blocks[i])) {
	314	dma_src[src_cnt] = dma_map_page(dev, blocks[i],
	315	offset, len,
	316	DMA_TO_DEVICE);
	317	coefs[src_cnt] = raid6_gfexp[i];
	318	src_cnt++;
	319	}
b2f46fd8 DW	320
	321	for (;;) {
	322	tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
b2141e69 N	323	src_cnt,
b2141e69 N	324	coefs,
b2f46fd8 DW	325	len, pqres,
	326	dma_flags);
	327	if (likely(tx))
	328	break;
	329	async_tx_quiesce(&submit->depend_tx);
	330	dma_async_issue_pending(chan);
	331	}
	332	async_tx_submit(chan, tx, submit);
	333
	334	return tx;
	335	} else {
	336	struct page *p_src = P(blocks, disks);
	337	struct page *q_src = Q(blocks, disks);
	338	enum async_tx_flags flags_orig = submit->flags;
	339	dma_async_tx_callback cb_fn_orig = submit->cb_fn;
	340	void *scribble = submit->scribble;
	341	void *cb_param_orig = submit->cb_param;
	342	void p, q, *s;
	343
	344	pr_debug("%s: (sync) disks: %d len: %zu\n",
	345	__func__, disks, len);
	346
	347	/* caller must provide a temporary result buffer and
	348	* allow the input parameters to be preserved
	349	*/
	350	BUG_ON(!spare \|\| !scribble);
	351
	352	/* wait for any prerequisite operations */
	353	async_tx_quiesce(&submit->depend_tx);
	354
	355	/* recompute p and/or q into the temporary buffer and then
	356	* check to see the result matches the current value
	357	*/
	358	tx = NULL;
	359	*pqres = 0;
	360	if (p_src) {
	361	init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
	362	NULL, NULL, scribble);
	363	tx = async_xor(spare, blocks, offset, disks-2, len, submit);
	364	async_tx_quiesce(&tx);
	365	p = page_address(p_src) + offset;
	366	s = page_address(spare) + offset;
	367	*pqres \|= !!memcmp(p, s, len) << SUM_CHECK_P;
	368	}
	369
	370	if (q_src) {
	371	P(blocks, disks) = NULL;
	372	Q(blocks, disks) = spare;
	373	init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
	374	tx = async_gen_syndrome(blocks, offset, disks, len, submit);
	375	async_tx_quiesce(&tx);
	376	q = page_address(q_src) + offset;
	377	s = page_address(spare) + offset;
	378	*pqres \|= !!memcmp(q, s, len) << SUM_CHECK_Q;
	379	}
	380
	381	/* restore P, Q and submit */
	382	P(blocks, disks) = p_src;
	383	Q(blocks, disks) = q_src;
	384
	385	submit->cb_fn = cb_fn_orig;
	386	submit->cb_param = cb_param_orig;
	387	submit->flags = flags_orig;
	388	async_tx_sync_epilog(submit);
389
390	return NULL;
391	}
392	}
393	EXPORT_SYMBOL_GPL(async_syndrome_val);
394
395	static int __init async_pq_init(void)
396	{
030b0772	397	pq_scribble_page = alloc_page(GFP_KERNEL);
b2f46fd8	398
030b0772	399	if (pq_scribble_page)
b2f46fd8 DW	400	return 0;
	401
	402	pr_err("%s: failed to allocate required spare page\n", __func__);
	403
	404	return -ENOMEM;
	405	}
	406
	407	static void __exit async_pq_exit(void)
	408	{
030b0772	409	put_page(pq_scribble_page);
b2f46fd8 DW	410	}
	411
	412	module_init(async_pq_init);
	413	module_exit(async_pq_exit);
	414
	415	MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
	416	MODULE_LICENSE("GPL");