1 files changed, 345 insertions, 0 deletions

diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
new file mode 100644
index 000000000..da75777f2
--- /dev/null
+++ b/crypto/async_tx/async_xor.c
@@ -0,0 +1,345 @@
+/*
+ * 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 dmaengine_unmap_data *unmap,
+	     struct async_submit_ctl *submit)
+{
+	struct dma_device *dma = chan->device;
+	struct dma_async_tx_descriptor *tx = NULL;
+	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 = 0;
+	int src_cnt = unmap->to_cnt;
+	int xor_src_cnt;
+	dma_addr_t dma_dest = unmap->addr[unmap->to_cnt];
+	dma_addr_t *src_list = unmap->addr;
+
+	while (src_cnt) {
+		dma_addr_t tmp;
+
+		submit->flags = flags_orig;
+		xor_src_cnt = min(src_cnt, (int)dma->max_xor);
+		/* if we are submitting additional xors, leave the chain open
+		 * and clear the callback parameters
+		 */
+		if (src_cnt > xor_src_cnt) {
+			submit->flags &= ~ASYNC_TX_ACK;
+			submit->flags |= ASYNC_TX_FENCE;
+			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;
+
+		/* Drivers force forward progress in case they can not provide a
+		 * descriptor
+		 */
+		tmp = src_list[0];
+		if (src_list > unmap->addr)
+			src_list[0] = dma_dest;
+		tx = dma->device_prep_dma_xor(chan, dma_dest, src_list,
+					      xor_src_cnt, unmap->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,
+						      src_list,
+						      xor_src_cnt, unmap->len,
+						      dma_flags);
+		}
+		src_list[0] = tmp;
+
+		dma_set_unmap(tx, unmap);
+		async_tx_submit(chan, tx, submit);
+		submit->depend_tx = tx;
+
+		if (src_cnt > xor_src_cnt) {
+			/* drop completed sources */
+			src_cnt -= xor_src_cnt;
+			/* use the intermediate result a source */
+			src_cnt++;
+			src_list += xor_src_cnt - 1;
+		} 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);
+	struct dma_device *device = chan ? chan->device : NULL;
+	struct dmaengine_unmap_data *unmap = NULL;
+
+	BUG_ON(src_cnt <= 1);
+
+	if (device)
+		unmap = dmaengine_get_unmap_data(device->dev, src_cnt+1, GFP_NOWAIT);
+
+	if (unmap && is_dma_xor_aligned(device, offset, 0, len)) {
+		struct dma_async_tx_descriptor *tx;
+		int i, j;
+
+		/* run the xor asynchronously */
+		pr_debug("%s (async): len: %zu\n", __func__, len);
+
+		unmap->len = len;
+		for (i = 0, j = 0; i < src_cnt; i++) {
+			if (!src_list[i])
+				continue;
+			unmap->to_cnt++;
+			unmap->addr[j++] = dma_map_page(device->dev, src_list[i],
+							offset, len, DMA_TO_DEVICE);
+		}
+
+		/* map it bidirectional as it may be re-used as a source */
+		unmap->addr[j] = dma_map_page(device->dev, dest, offset, len,
+					      DMA_BIDIRECTIONAL);
+		unmap->bidi_cnt = 1;
+
+		tx = do_async_xor(chan, unmap, submit);
+		dmaengine_unmap_put(unmap);
+		return tx;
+	} else {
+		dmaengine_unmap_put(unmap);
+		/* 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)
+{
+	return !memchr_inv(page_address(p) + offset, 0, len);
+}
+
+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;
+	struct dmaengine_unmap_data *unmap = NULL;
+
+	BUG_ON(src_cnt <= 1);
+
+	if (device)
+		unmap = dmaengine_get_unmap_data(device->dev, src_cnt, GFP_NOWAIT);
+
+	if (unmap && 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++) {
+			unmap->addr[i] = dma_map_page(device->dev, src_list[i],
+						      offset, len, DMA_TO_DEVICE);
+			unmap->to_cnt++;
+		}
+		unmap->len = len;
+
+		tx = device->device_prep_dma_xor_val(chan, unmap->addr, 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,
+					unmap->addr, src_cnt, len, result,
+					dma_prep_flags);
+			}
+		}
+		dma_set_unmap(tx, unmap);
+		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;
+	}
+	dmaengine_unmap_put(unmap);
+
+	return tx;
+}
+EXPORT_SYMBOL_GPL(async_xor_val);
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api");
+MODULE_LICENSE("GPL");