--- /dev/null
+/*
+ * 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/module.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,
+ const unsigned char *scfs, int disks,
+ struct dmaengine_unmap_data *unmap,
+ enum dma_ctrl_flags dma_flags,
+ struct async_submit_ctl *submit)
+{
+ struct dma_async_tx_descriptor *tx = NULL;
+ struct dma_device *dma = chan->device;
+ 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 short pq_src_cnt;
+ dma_addr_t dma_dest[2];
+ int src_off = 0;
+
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_flags |= DMA_PREP_FENCE;
+
+ 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;
+ submit->cb_fn = NULL;
+ submit->cb_param = NULL;
+ } else {
+ submit->cb_fn = cb_fn_orig;
+ submit->cb_param = cb_param_orig;
+ if (cb_fn_orig)
+ dma_flags |= DMA_PREP_INTERRUPT;
+ }
+
+ /* Drivers force forward progress in case they can not provide
+ * a descriptor
+ */
+ for (;;) {
+ dma_dest[0] = unmap->addr[disks - 2];
+ dma_dest[1] = unmap->addr[disks - 1];
+ tx = dma->device_prep_dma_pq(chan, dma_dest,
+ &unmap->addr[src_off],
+ pq_src_cnt,
+ &scfs[src_off], unmap->len,
+ dma_flags);
+ if (likely(tx))
+ break;
+ async_tx_quiesce(&submit->depend_tx);
+ dma_async_issue_pending(chan);
+ }
+
+ dma_set_unmap(tx, unmap);
+ 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;
+ int start = -1, stop = disks - 3;
+
+ 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;
+ if (i < disks - 2) {
+ stop = i;
+ if (start == -1)
+ start = i;
+ }
+ }
+ }
+ if (submit->flags & ASYNC_TX_PQ_XOR_DST) {
+ BUG_ON(!raid6_call.xor_syndrome);
+ if (start >= 0)
+ raid6_call.xor_syndrome(disks, start, stop, len, srcs);
+ } else
+ 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.
+ */
+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;
+ struct dmaengine_unmap_data *unmap = NULL;
+
+ BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks)));
+
+ if (device)
+ unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO);
+
+ /* XORing P/Q is only implemented in software */
+ if (unmap && !(submit->flags & ASYNC_TX_PQ_XOR_DST) &&
+ (src_cnt <= dma_maxpq(device, 0) ||
+ dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
+ is_dma_pq_aligned(device, offset, 0, len)) {
+ struct dma_async_tx_descriptor *tx;
+ enum dma_ctrl_flags dma_flags = 0;
+ unsigned char coefs[src_cnt];
+ int i, j;
+
+ /* run the p+q asynchronously */
+ pr_debug("%s: (async) disks: %d len: %zu\n",
+ __func__, disks, len);
+
+ /* convert source addresses being careful to collapse 'empty'
+ * sources and update the coefficients accordingly
+ */
+ unmap->len = len;
+ for (i = 0, j = 0; i < src_cnt; i++) {
+ if (blocks[i] == NULL)
+ continue;
+ unmap->addr[j] = dma_map_page(device->dev, blocks[i], offset,
+ len, DMA_TO_DEVICE);
+ coefs[j] = raid6_gfexp[i];
+ unmap->to_cnt++;
+ j++;
+ }
+
+ /*
+ * DMAs use destinations as sources,
+ * so use BIDIRECTIONAL mapping
+ */
+ unmap->bidi_cnt++;
+ if (P(blocks, disks))
+ unmap->addr[j++] = dma_map_page(device->dev, P(blocks, disks),
+ offset, len, DMA_BIDIRECTIONAL);
+ else {
+ unmap->addr[j++] = 0;
+ dma_flags |= DMA_PREP_PQ_DISABLE_P;
+ }
+
+ unmap->bidi_cnt++;
+ if (Q(blocks, disks))
+ unmap->addr[j++] = dma_map_page(device->dev, Q(blocks, disks),
+ offset, len, DMA_BIDIRECTIONAL);
+ else {
+ unmap->addr[j++] = 0;
+ dma_flags |= DMA_PREP_PQ_DISABLE_Q;
+ }
+
+ tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, submit);
+ dmaengine_unmap_put(unmap);
+ return tx;
+ }
+
+ dmaengine_unmap_put(unmap);
+
+ /* 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;
+ struct dmaengine_unmap_data *unmap = NULL;
+
+ BUG_ON(disks < 4);
+
+ if (device)
+ unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO);
+
+ if (unmap && disks <= dma_maxpq(device, 0) &&
+ is_dma_pq_aligned(device, offset, 0, len)) {
+ struct device *dev = device->dev;
+ dma_addr_t pq[2];
+ int i, j = 0, src_cnt = 0;
+
+ pr_debug("%s: (async) disks: %d len: %zu\n",
+ __func__, disks, len);
+
+ unmap->len = len;
+ for (i = 0; i < disks-2; i++)
+ if (likely(blocks[i])) {
+ unmap->addr[j] = dma_map_page(dev, blocks[i],
+ offset, len,
+ DMA_TO_DEVICE);
+ coefs[j] = raid6_gfexp[i];
+ unmap->to_cnt++;
+ src_cnt++;
+ j++;
+ }
+
+ if (!P(blocks, disks)) {
+ pq[0] = 0;
+ dma_flags |= DMA_PREP_PQ_DISABLE_P;
+ } else {
+ pq[0] = dma_map_page(dev, P(blocks, disks),
+ offset, len,
+ DMA_TO_DEVICE);
+ unmap->addr[j++] = pq[0];
+ unmap->to_cnt++;
+ }
+ if (!Q(blocks, disks)) {
+ pq[1] = 0;
+ dma_flags |= DMA_PREP_PQ_DISABLE_Q;
+ } else {
+ pq[1] = dma_map_page(dev, Q(blocks, disks),
+ offset, len,
+ DMA_TO_DEVICE);
+ unmap->addr[j++] = pq[1];
+ unmap->to_cnt++;
+ }
+
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_flags |= DMA_PREP_FENCE;
+ for (;;) {
+ tx = device->device_prep_dma_pq_val(chan, pq,
+ unmap->addr,
+ src_cnt,
+ coefs,
+ len, pqres,
+ dma_flags);
+ if (likely(tx))
+ break;
+ async_tx_quiesce(&submit->depend_tx);
+ dma_async_issue_pending(chan);
+ }
+
+ dma_set_unmap(tx, unmap);
+ 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");
Code Review / kvmfornfv.git / blobdiff