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-rw-r--r--crypto/async_tx/async_xor.c338
1 files changed, 338 insertions, 0 deletions
diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
new file mode 100644
index 00000000..079ae8ca
--- /dev/null
+++ b/crypto/async_tx/async_xor.c
@@ -0,0 +1,338 @@
+/*
+ * 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");
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