crypto/async_tx/async_xor.c - arm/linux - Git at Google

 /*
  * 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");
	/*
	* 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");