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![Yufen Yu](/assets/img/avatar_default.png)
For now, syndrome compute functions require common offset in the pages array. However, we expect them to support different offset when try to use shared page in the following. Simplily covert them by adding page offset where each page address are referred. Since the only caller of async_gen_syndrome() and async_syndrome_val() are in raid6, we don't want to reserve the old interface but modify the interface directly. After that, replacing old interfaces with new ones for raid6 and raid6test. Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Song Liu <songliubraving@fb.com>
463 lines
13 KiB
C
463 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com>
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* Copyright(c) 2009 Intel Corporation
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*/
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/dma-mapping.h>
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#include <linux/raid/pq.h>
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#include <linux/async_tx.h>
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#include <linux/gfp.h>
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/**
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* pq_scribble_page - space to hold throwaway P or Q buffer for
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* synchronous gen_syndrome
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*/
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static struct page *pq_scribble_page;
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/* the struct page *blocks[] parameter passed to async_gen_syndrome()
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* and async_syndrome_val() contains the 'P' destination address at
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* blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
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*
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* note: these are macros as they are used as lvalues
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*/
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#define P(b, d) (b[d-2])
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#define Q(b, d) (b[d-1])
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#define MAX_DISKS 255
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/**
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* do_async_gen_syndrome - asynchronously calculate P and/or Q
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*/
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static __async_inline struct dma_async_tx_descriptor *
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do_async_gen_syndrome(struct dma_chan *chan,
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const unsigned char *scfs, int disks,
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struct dmaengine_unmap_data *unmap,
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enum dma_ctrl_flags dma_flags,
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struct async_submit_ctl *submit)
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{
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struct dma_async_tx_descriptor *tx = NULL;
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struct dma_device *dma = chan->device;
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enum async_tx_flags flags_orig = submit->flags;
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dma_async_tx_callback cb_fn_orig = submit->cb_fn;
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dma_async_tx_callback cb_param_orig = submit->cb_param;
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int src_cnt = disks - 2;
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unsigned short pq_src_cnt;
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dma_addr_t dma_dest[2];
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int src_off = 0;
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while (src_cnt > 0) {
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submit->flags = flags_orig;
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pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
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/* if we are submitting additional pqs, leave the chain open,
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* clear the callback parameters, and leave the destination
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* buffers mapped
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*/
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if (src_cnt > pq_src_cnt) {
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submit->flags &= ~ASYNC_TX_ACK;
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submit->flags |= ASYNC_TX_FENCE;
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submit->cb_fn = NULL;
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submit->cb_param = NULL;
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} else {
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submit->cb_fn = cb_fn_orig;
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submit->cb_param = cb_param_orig;
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if (cb_fn_orig)
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dma_flags |= DMA_PREP_INTERRUPT;
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}
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if (submit->flags & ASYNC_TX_FENCE)
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dma_flags |= DMA_PREP_FENCE;
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/* Drivers force forward progress in case they can not provide
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* a descriptor
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*/
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for (;;) {
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dma_dest[0] = unmap->addr[disks - 2];
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dma_dest[1] = unmap->addr[disks - 1];
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tx = dma->device_prep_dma_pq(chan, dma_dest,
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&unmap->addr[src_off],
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pq_src_cnt,
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&scfs[src_off], unmap->len,
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dma_flags);
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if (likely(tx))
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break;
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async_tx_quiesce(&submit->depend_tx);
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dma_async_issue_pending(chan);
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}
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dma_set_unmap(tx, unmap);
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async_tx_submit(chan, tx, submit);
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submit->depend_tx = tx;
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/* drop completed sources */
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src_cnt -= pq_src_cnt;
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src_off += pq_src_cnt;
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dma_flags |= DMA_PREP_CONTINUE;
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}
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return tx;
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}
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/**
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* do_sync_gen_syndrome - synchronously calculate a raid6 syndrome
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*/
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static void
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do_sync_gen_syndrome(struct page **blocks, unsigned int *offsets, int disks,
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size_t len, struct async_submit_ctl *submit)
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{
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void **srcs;
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int i;
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int start = -1, stop = disks - 3;
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if (submit->scribble)
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srcs = submit->scribble;
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else
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srcs = (void **) blocks;
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for (i = 0; i < disks; i++) {
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if (blocks[i] == NULL) {
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BUG_ON(i > disks - 3); /* P or Q can't be zero */
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srcs[i] = (void*)raid6_empty_zero_page;
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} else {
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srcs[i] = page_address(blocks[i]) + offsets[i];
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if (i < disks - 2) {
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stop = i;
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if (start == -1)
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start = i;
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}
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}
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}
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if (submit->flags & ASYNC_TX_PQ_XOR_DST) {
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BUG_ON(!raid6_call.xor_syndrome);
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if (start >= 0)
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raid6_call.xor_syndrome(disks, start, stop, len, srcs);
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} else
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raid6_call.gen_syndrome(disks, len, srcs);
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async_tx_sync_epilog(submit);
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}
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static inline bool
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is_dma_pq_aligned_offs(struct dma_device *dev, unsigned int *offs,
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int src_cnt, size_t len)
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{
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int i;
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for (i = 0; i < src_cnt; i++) {
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if (!is_dma_pq_aligned(dev, offs[i], 0, len))
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return false;
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}
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return true;
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}
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/**
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* async_gen_syndrome - asynchronously calculate a raid6 syndrome
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* @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
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* @offsets: offset array into each block (src and dest) to start transaction
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* @disks: number of blocks (including missing P or Q, see below)
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* @len: length of operation in bytes
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* @submit: submission/completion modifiers
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*
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* General note: This routine assumes a field of GF(2^8) with a
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* primitive polynomial of 0x11d and a generator of {02}.
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*
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* 'disks' note: callers can optionally omit either P or Q (but not
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* both) from the calculation by setting blocks[disks-2] or
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* blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <=
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* PAGE_SIZE as a temporary buffer of this size is used in the
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* synchronous path. 'disks' always accounts for both destination
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* buffers. If any source buffers (blocks[i] where i < disks - 2) are
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* set to NULL those buffers will be replaced with the raid6_zero_page
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* in the synchronous path and omitted in the hardware-asynchronous
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* path.
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*/
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struct dma_async_tx_descriptor *
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async_gen_syndrome(struct page **blocks, unsigned int *offsets, int disks,
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size_t len, struct async_submit_ctl *submit)
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{
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int src_cnt = disks - 2;
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struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
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&P(blocks, disks), 2,
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blocks, src_cnt, len);
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struct dma_device *device = chan ? chan->device : NULL;
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struct dmaengine_unmap_data *unmap = NULL;
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BUG_ON(disks > MAX_DISKS || !(P(blocks, disks) || Q(blocks, disks)));
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if (device)
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unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
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/* XORing P/Q is only implemented in software */
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if (unmap && !(submit->flags & ASYNC_TX_PQ_XOR_DST) &&
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(src_cnt <= dma_maxpq(device, 0) ||
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dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
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is_dma_pq_aligned_offs(device, offsets, disks, len)) {
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struct dma_async_tx_descriptor *tx;
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enum dma_ctrl_flags dma_flags = 0;
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unsigned char coefs[MAX_DISKS];
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int i, j;
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/* run the p+q asynchronously */
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pr_debug("%s: (async) disks: %d len: %zu\n",
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__func__, disks, len);
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/* convert source addresses being careful to collapse 'empty'
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* sources and update the coefficients accordingly
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*/
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unmap->len = len;
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for (i = 0, j = 0; i < src_cnt; i++) {
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if (blocks[i] == NULL)
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continue;
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unmap->addr[j] = dma_map_page(device->dev, blocks[i],
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offsets[i], len, DMA_TO_DEVICE);
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coefs[j] = raid6_gfexp[i];
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unmap->to_cnt++;
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j++;
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}
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/*
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* DMAs use destinations as sources,
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* so use BIDIRECTIONAL mapping
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*/
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unmap->bidi_cnt++;
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if (P(blocks, disks))
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unmap->addr[j++] = dma_map_page(device->dev, P(blocks, disks),
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P(offsets, disks),
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len, DMA_BIDIRECTIONAL);
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else {
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unmap->addr[j++] = 0;
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dma_flags |= DMA_PREP_PQ_DISABLE_P;
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}
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unmap->bidi_cnt++;
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if (Q(blocks, disks))
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unmap->addr[j++] = dma_map_page(device->dev, Q(blocks, disks),
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Q(offsets, disks),
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len, DMA_BIDIRECTIONAL);
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else {
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unmap->addr[j++] = 0;
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dma_flags |= DMA_PREP_PQ_DISABLE_Q;
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}
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tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, submit);
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dmaengine_unmap_put(unmap);
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return tx;
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}
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dmaengine_unmap_put(unmap);
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/* run the pq synchronously */
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pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
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/* wait for any prerequisite operations */
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async_tx_quiesce(&submit->depend_tx);
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if (!P(blocks, disks)) {
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P(blocks, disks) = pq_scribble_page;
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P(offsets, disks) = 0;
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}
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if (!Q(blocks, disks)) {
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Q(blocks, disks) = pq_scribble_page;
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Q(offsets, disks) = 0;
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}
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do_sync_gen_syndrome(blocks, offsets, disks, len, submit);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(async_gen_syndrome);
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static inline struct dma_chan *
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pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len)
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{
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#ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
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return NULL;
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#endif
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return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks,
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disks, len);
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}
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/**
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* async_syndrome_val - asynchronously validate a raid6 syndrome
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* @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
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* @offset: common offset into each block (src and dest) to start transaction
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* @disks: number of blocks (including missing P or Q, see below)
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* @len: length of operation in bytes
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* @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set
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* @spare: temporary result buffer for the synchronous case
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* @s_off: spare buffer page offset
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* @submit: submission / completion modifiers
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*
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* The same notes from async_gen_syndrome apply to the 'blocks',
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* and 'disks' parameters of this routine. The synchronous path
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* requires a temporary result buffer and submit->scribble to be
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* specified.
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*/
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struct dma_async_tx_descriptor *
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async_syndrome_val(struct page **blocks, unsigned int *offsets, int disks,
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size_t len, enum sum_check_flags *pqres, struct page *spare,
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unsigned int s_off, struct async_submit_ctl *submit)
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{
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struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
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struct dma_device *device = chan ? chan->device : NULL;
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struct dma_async_tx_descriptor *tx;
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unsigned char coefs[MAX_DISKS];
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enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
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struct dmaengine_unmap_data *unmap = NULL;
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BUG_ON(disks < 4 || disks > MAX_DISKS);
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if (device)
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unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
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if (unmap && disks <= dma_maxpq(device, 0) &&
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is_dma_pq_aligned_offs(device, offsets, disks, len)) {
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struct device *dev = device->dev;
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dma_addr_t pq[2];
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int i, j = 0, src_cnt = 0;
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pr_debug("%s: (async) disks: %d len: %zu\n",
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__func__, disks, len);
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unmap->len = len;
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for (i = 0; i < disks-2; i++)
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if (likely(blocks[i])) {
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unmap->addr[j] = dma_map_page(dev, blocks[i],
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offsets[i], len,
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DMA_TO_DEVICE);
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coefs[j] = raid6_gfexp[i];
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unmap->to_cnt++;
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src_cnt++;
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j++;
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}
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if (!P(blocks, disks)) {
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pq[0] = 0;
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dma_flags |= DMA_PREP_PQ_DISABLE_P;
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} else {
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pq[0] = dma_map_page(dev, P(blocks, disks),
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P(offsets, disks), len,
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DMA_TO_DEVICE);
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unmap->addr[j++] = pq[0];
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unmap->to_cnt++;
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}
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if (!Q(blocks, disks)) {
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pq[1] = 0;
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dma_flags |= DMA_PREP_PQ_DISABLE_Q;
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} else {
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pq[1] = dma_map_page(dev, Q(blocks, disks),
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Q(offsets, disks), len,
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DMA_TO_DEVICE);
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unmap->addr[j++] = pq[1];
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unmap->to_cnt++;
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}
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if (submit->flags & ASYNC_TX_FENCE)
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dma_flags |= DMA_PREP_FENCE;
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for (;;) {
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tx = device->device_prep_dma_pq_val(chan, pq,
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unmap->addr,
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src_cnt,
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coefs,
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len, pqres,
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dma_flags);
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if (likely(tx))
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break;
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async_tx_quiesce(&submit->depend_tx);
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dma_async_issue_pending(chan);
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}
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dma_set_unmap(tx, unmap);
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async_tx_submit(chan, tx, submit);
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} else {
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struct page *p_src = P(blocks, disks);
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unsigned int p_off = P(offsets, disks);
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struct page *q_src = Q(blocks, disks);
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unsigned int q_off = Q(offsets, disks);
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enum async_tx_flags flags_orig = submit->flags;
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dma_async_tx_callback cb_fn_orig = submit->cb_fn;
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void *scribble = submit->scribble;
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void *cb_param_orig = submit->cb_param;
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void *p, *q, *s;
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pr_debug("%s: (sync) disks: %d len: %zu\n",
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__func__, disks, len);
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/* caller must provide a temporary result buffer and
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* allow the input parameters to be preserved
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*/
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BUG_ON(!spare || !scribble);
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/* wait for any prerequisite operations */
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async_tx_quiesce(&submit->depend_tx);
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/* recompute p and/or q into the temporary buffer and then
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* check to see the result matches the current value
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*/
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tx = NULL;
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*pqres = 0;
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if (p_src) {
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init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
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NULL, NULL, scribble);
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tx = async_xor_offs(spare, s_off,
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blocks, offsets, disks-2, len, submit);
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async_tx_quiesce(&tx);
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p = page_address(p_src) + p_off;
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s = page_address(spare) + s_off;
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*pqres |= !!memcmp(p, s, len) << SUM_CHECK_P;
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}
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if (q_src) {
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P(blocks, disks) = NULL;
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Q(blocks, disks) = spare;
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Q(offsets, disks) = s_off;
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init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
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tx = async_gen_syndrome(blocks, offsets, disks,
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len, submit);
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async_tx_quiesce(&tx);
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q = page_address(q_src) + q_off;
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s = page_address(spare) + s_off;
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*pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q;
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}
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/* restore P, Q and submit */
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P(blocks, disks) = p_src;
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P(offsets, disks) = p_off;
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Q(blocks, disks) = q_src;
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Q(offsets, disks) = q_off;
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submit->cb_fn = cb_fn_orig;
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submit->cb_param = cb_param_orig;
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submit->flags = flags_orig;
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async_tx_sync_epilog(submit);
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tx = NULL;
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}
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dmaengine_unmap_put(unmap);
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return tx;
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}
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EXPORT_SYMBOL_GPL(async_syndrome_val);
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static int __init async_pq_init(void)
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{
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pq_scribble_page = alloc_page(GFP_KERNEL);
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if (pq_scribble_page)
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return 0;
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pr_err("%s: failed to allocate required spare page\n", __func__);
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return -ENOMEM;
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}
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static void __exit async_pq_exit(void)
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{
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__free_page(pq_scribble_page);
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}
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module_init(async_pq_init);
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module_exit(async_pq_exit);
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MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
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MODULE_LICENSE("GPL");
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