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594 lines
16 KiB
594 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Asynchronous RAID-6 recovery calculations ASYNC_TX API. |
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* Copyright(c) 2009 Intel Corporation |
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* |
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* based on raid6recov.c: |
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* Copyright 2002 H. Peter Anvin |
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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/dmaengine.h> |
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static struct dma_async_tx_descriptor * |
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async_sum_product(struct page *dest, unsigned int d_off, |
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struct page **srcs, unsigned int *src_offs, unsigned char *coef, |
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size_t len, struct async_submit_ctl *submit) |
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{ |
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struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, |
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&dest, 1, srcs, 2, len); |
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struct dma_device *dma = chan ? chan->device : NULL; |
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struct dmaengine_unmap_data *unmap = NULL; |
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const u8 *amul, *bmul; |
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u8 ax, bx; |
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u8 *a, *b, *c; |
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if (dma) |
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unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT); |
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if (unmap) { |
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struct device *dev = dma->dev; |
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dma_addr_t pq[2]; |
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struct dma_async_tx_descriptor *tx; |
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enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P; |
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if (submit->flags & ASYNC_TX_FENCE) |
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dma_flags |= DMA_PREP_FENCE; |
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unmap->addr[0] = dma_map_page(dev, srcs[0], src_offs[0], |
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len, DMA_TO_DEVICE); |
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unmap->addr[1] = dma_map_page(dev, srcs[1], src_offs[1], |
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len, DMA_TO_DEVICE); |
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unmap->to_cnt = 2; |
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unmap->addr[2] = dma_map_page(dev, dest, d_off, |
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len, DMA_BIDIRECTIONAL); |
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unmap->bidi_cnt = 1; |
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/* engine only looks at Q, but expects it to follow P */ |
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pq[1] = unmap->addr[2]; |
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unmap->len = len; |
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tx = dma->device_prep_dma_pq(chan, pq, unmap->addr, 2, coef, |
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len, dma_flags); |
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if (tx) { |
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dma_set_unmap(tx, unmap); |
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async_tx_submit(chan, tx, submit); |
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dmaengine_unmap_put(unmap); |
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return tx; |
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} |
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|
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/* could not get a descriptor, unmap and fall through to |
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* the synchronous path |
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*/ |
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dmaengine_unmap_put(unmap); |
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} |
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|
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/* run the operation synchronously */ |
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async_tx_quiesce(&submit->depend_tx); |
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amul = raid6_gfmul[coef[0]]; |
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bmul = raid6_gfmul[coef[1]]; |
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a = page_address(srcs[0]) + src_offs[0]; |
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b = page_address(srcs[1]) + src_offs[1]; |
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c = page_address(dest) + d_off; |
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while (len--) { |
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ax = amul[*a++]; |
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bx = bmul[*b++]; |
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*c++ = ax ^ bx; |
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} |
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return NULL; |
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} |
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static struct dma_async_tx_descriptor * |
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async_mult(struct page *dest, unsigned int d_off, struct page *src, |
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unsigned int s_off, u8 coef, size_t len, |
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struct async_submit_ctl *submit) |
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{ |
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struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, |
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&dest, 1, &src, 1, len); |
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struct dma_device *dma = chan ? chan->device : NULL; |
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struct dmaengine_unmap_data *unmap = NULL; |
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const u8 *qmul; /* Q multiplier table */ |
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u8 *d, *s; |
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if (dma) |
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unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT); |
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if (unmap) { |
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dma_addr_t dma_dest[2]; |
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struct device *dev = dma->dev; |
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struct dma_async_tx_descriptor *tx; |
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enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P; |
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if (submit->flags & ASYNC_TX_FENCE) |
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dma_flags |= DMA_PREP_FENCE; |
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unmap->addr[0] = dma_map_page(dev, src, s_off, |
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len, DMA_TO_DEVICE); |
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unmap->to_cnt++; |
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unmap->addr[1] = dma_map_page(dev, dest, d_off, |
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len, DMA_BIDIRECTIONAL); |
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dma_dest[1] = unmap->addr[1]; |
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unmap->bidi_cnt++; |
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unmap->len = len; |
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/* this looks funny, but the engine looks for Q at |
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* dma_dest[1] and ignores dma_dest[0] as a dest |
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* due to DMA_PREP_PQ_DISABLE_P |
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*/ |
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tx = dma->device_prep_dma_pq(chan, dma_dest, unmap->addr, |
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1, &coef, len, dma_flags); |
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if (tx) { |
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dma_set_unmap(tx, unmap); |
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dmaengine_unmap_put(unmap); |
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async_tx_submit(chan, tx, submit); |
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return tx; |
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} |
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/* could not get a descriptor, unmap and fall through to |
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* the synchronous path |
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*/ |
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dmaengine_unmap_put(unmap); |
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} |
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/* no channel available, or failed to allocate a descriptor, so |
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* perform the operation synchronously |
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*/ |
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async_tx_quiesce(&submit->depend_tx); |
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qmul = raid6_gfmul[coef]; |
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d = page_address(dest) + d_off; |
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s = page_address(src) + s_off; |
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while (len--) |
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*d++ = qmul[*s++]; |
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return NULL; |
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} |
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static struct dma_async_tx_descriptor * |
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__2data_recov_4(int disks, size_t bytes, int faila, int failb, |
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struct page **blocks, unsigned int *offs, |
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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 page *p, *q, *a, *b; |
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unsigned int p_off, q_off, a_off, b_off; |
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struct page *srcs[2]; |
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unsigned int src_offs[2]; |
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unsigned char coef[2]; |
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enum async_tx_flags flags = submit->flags; |
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dma_async_tx_callback cb_fn = submit->cb_fn; |
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void *cb_param = submit->cb_param; |
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void *scribble = submit->scribble; |
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p = blocks[disks-2]; |
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p_off = offs[disks-2]; |
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q = blocks[disks-1]; |
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q_off = offs[disks-1]; |
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a = blocks[faila]; |
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a_off = offs[faila]; |
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b = blocks[failb]; |
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b_off = offs[failb]; |
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/* in the 4 disk case P + Pxy == P and Q + Qxy == Q */ |
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/* Dx = A*(P+Pxy) + B*(Q+Qxy) */ |
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srcs[0] = p; |
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src_offs[0] = p_off; |
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srcs[1] = q; |
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src_offs[1] = q_off; |
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coef[0] = raid6_gfexi[failb-faila]; |
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coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; |
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init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
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tx = async_sum_product(b, b_off, srcs, src_offs, coef, bytes, submit); |
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/* Dy = P+Pxy+Dx */ |
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srcs[0] = p; |
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src_offs[0] = p_off; |
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srcs[1] = b; |
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src_offs[1] = b_off; |
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init_async_submit(submit, flags | ASYNC_TX_XOR_ZERO_DST, tx, cb_fn, |
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cb_param, scribble); |
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tx = async_xor_offs(a, a_off, srcs, src_offs, 2, bytes, submit); |
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return tx; |
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} |
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static struct dma_async_tx_descriptor * |
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__2data_recov_5(int disks, size_t bytes, int faila, int failb, |
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struct page **blocks, unsigned int *offs, |
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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 page *p, *q, *g, *dp, *dq; |
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unsigned int p_off, q_off, g_off, dp_off, dq_off; |
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struct page *srcs[2]; |
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unsigned int src_offs[2]; |
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unsigned char coef[2]; |
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enum async_tx_flags flags = submit->flags; |
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dma_async_tx_callback cb_fn = submit->cb_fn; |
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void *cb_param = submit->cb_param; |
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void *scribble = submit->scribble; |
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int good_srcs, good, i; |
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good_srcs = 0; |
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good = -1; |
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for (i = 0; i < disks-2; i++) { |
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if (blocks[i] == NULL) |
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continue; |
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if (i == faila || i == failb) |
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continue; |
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good = i; |
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good_srcs++; |
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} |
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BUG_ON(good_srcs > 1); |
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p = blocks[disks-2]; |
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p_off = offs[disks-2]; |
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q = blocks[disks-1]; |
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q_off = offs[disks-1]; |
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g = blocks[good]; |
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g_off = offs[good]; |
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|
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/* Compute syndrome with zero for the missing data pages |
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* Use the dead data pages as temporary storage for delta p and |
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* delta q |
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*/ |
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dp = blocks[faila]; |
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dp_off = offs[faila]; |
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dq = blocks[failb]; |
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dq_off = offs[failb]; |
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init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
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tx = async_memcpy(dp, g, dp_off, g_off, bytes, submit); |
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init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
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tx = async_mult(dq, dq_off, g, g_off, |
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raid6_gfexp[good], bytes, submit); |
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/* compute P + Pxy */ |
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srcs[0] = dp; |
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src_offs[0] = dp_off; |
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srcs[1] = p; |
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src_offs[1] = p_off; |
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init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
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NULL, NULL, scribble); |
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tx = async_xor_offs(dp, dp_off, srcs, src_offs, 2, bytes, submit); |
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/* compute Q + Qxy */ |
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srcs[0] = dq; |
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src_offs[0] = dq_off; |
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srcs[1] = q; |
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src_offs[1] = q_off; |
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init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
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NULL, NULL, scribble); |
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tx = async_xor_offs(dq, dq_off, srcs, src_offs, 2, bytes, submit); |
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/* Dx = A*(P+Pxy) + B*(Q+Qxy) */ |
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srcs[0] = dp; |
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src_offs[0] = dp_off; |
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srcs[1] = dq; |
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src_offs[1] = dq_off; |
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coef[0] = raid6_gfexi[failb-faila]; |
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coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; |
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init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
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tx = async_sum_product(dq, dq_off, srcs, src_offs, coef, bytes, submit); |
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/* Dy = P+Pxy+Dx */ |
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srcs[0] = dp; |
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src_offs[0] = dp_off; |
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srcs[1] = dq; |
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src_offs[1] = dq_off; |
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init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
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cb_param, scribble); |
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tx = async_xor_offs(dp, dp_off, srcs, src_offs, 2, bytes, submit); |
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return tx; |
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} |
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static struct dma_async_tx_descriptor * |
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__2data_recov_n(int disks, size_t bytes, int faila, int failb, |
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struct page **blocks, unsigned int *offs, |
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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 page *p, *q, *dp, *dq; |
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unsigned int p_off, q_off, dp_off, dq_off; |
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struct page *srcs[2]; |
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unsigned int src_offs[2]; |
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unsigned char coef[2]; |
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enum async_tx_flags flags = submit->flags; |
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dma_async_tx_callback cb_fn = submit->cb_fn; |
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void *cb_param = submit->cb_param; |
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void *scribble = submit->scribble; |
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p = blocks[disks-2]; |
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p_off = offs[disks-2]; |
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q = blocks[disks-1]; |
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q_off = offs[disks-1]; |
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/* Compute syndrome with zero for the missing data pages |
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* Use the dead data pages as temporary storage for |
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* delta p and delta q |
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*/ |
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dp = blocks[faila]; |
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dp_off = offs[faila]; |
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blocks[faila] = NULL; |
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blocks[disks-2] = dp; |
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offs[disks-2] = dp_off; |
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dq = blocks[failb]; |
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dq_off = offs[failb]; |
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blocks[failb] = NULL; |
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blocks[disks-1] = dq; |
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offs[disks-1] = dq_off; |
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init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
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tx = async_gen_syndrome(blocks, offs, disks, bytes, submit); |
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/* Restore pointer table */ |
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blocks[faila] = dp; |
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offs[faila] = dp_off; |
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blocks[failb] = dq; |
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offs[failb] = dq_off; |
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blocks[disks-2] = p; |
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offs[disks-2] = p_off; |
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blocks[disks-1] = q; |
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offs[disks-1] = q_off; |
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/* compute P + Pxy */ |
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srcs[0] = dp; |
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src_offs[0] = dp_off; |
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srcs[1] = p; |
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src_offs[1] = p_off; |
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init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
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NULL, NULL, scribble); |
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tx = async_xor_offs(dp, dp_off, srcs, src_offs, 2, bytes, submit); |
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/* compute Q + Qxy */ |
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srcs[0] = dq; |
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src_offs[0] = dq_off; |
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srcs[1] = q; |
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src_offs[1] = q_off; |
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init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
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NULL, NULL, scribble); |
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tx = async_xor_offs(dq, dq_off, srcs, src_offs, 2, bytes, submit); |
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/* Dx = A*(P+Pxy) + B*(Q+Qxy) */ |
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srcs[0] = dp; |
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src_offs[0] = dp_off; |
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srcs[1] = dq; |
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src_offs[1] = dq_off; |
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coef[0] = raid6_gfexi[failb-faila]; |
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coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; |
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init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
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tx = async_sum_product(dq, dq_off, srcs, src_offs, coef, bytes, submit); |
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/* Dy = P+Pxy+Dx */ |
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srcs[0] = dp; |
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src_offs[0] = dp_off; |
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srcs[1] = dq; |
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src_offs[1] = dq_off; |
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init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
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cb_param, scribble); |
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tx = async_xor_offs(dp, dp_off, srcs, src_offs, 2, bytes, submit); |
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return tx; |
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} |
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/** |
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* async_raid6_2data_recov - asynchronously calculate two missing data blocks |
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* @disks: number of disks in the RAID-6 array |
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* @bytes: block size |
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* @faila: first failed drive index |
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* @failb: second failed drive index |
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* @blocks: array of source pointers where the last two entries are p and q |
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* @offs: array of offset for pages in blocks |
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* @submit: submission/completion modifiers |
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*/ |
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struct dma_async_tx_descriptor * |
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async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb, |
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struct page **blocks, unsigned int *offs, |
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struct async_submit_ctl *submit) |
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{ |
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void *scribble = submit->scribble; |
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int non_zero_srcs, i; |
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BUG_ON(faila == failb); |
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if (failb < faila) |
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swap(faila, failb); |
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pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); |
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|
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/* if a dma resource is not available or a scribble buffer is not |
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* available punt to the synchronous path. In the 'dma not |
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* available' case be sure to use the scribble buffer to |
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* preserve the content of 'blocks' as the caller intended. |
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*/ |
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if (!async_dma_find_channel(DMA_PQ) || !scribble) { |
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void **ptrs = scribble ? scribble : (void **) blocks; |
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async_tx_quiesce(&submit->depend_tx); |
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for (i = 0; i < disks; i++) |
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if (blocks[i] == NULL) |
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ptrs[i] = (void *) raid6_empty_zero_page; |
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else |
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ptrs[i] = page_address(blocks[i]) + offs[i]; |
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raid6_2data_recov(disks, bytes, faila, failb, ptrs); |
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async_tx_sync_epilog(submit); |
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return NULL; |
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} |
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non_zero_srcs = 0; |
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for (i = 0; i < disks-2 && non_zero_srcs < 4; i++) |
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if (blocks[i]) |
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non_zero_srcs++; |
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switch (non_zero_srcs) { |
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case 0: |
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case 1: |
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/* There must be at least 2 sources - the failed devices. */ |
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BUG(); |
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case 2: |
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/* dma devices do not uniformly understand a zero source pq |
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* operation (in contrast to the synchronous case), so |
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* explicitly handle the special case of a 4 disk array with |
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* both data disks missing. |
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*/ |
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return __2data_recov_4(disks, bytes, faila, failb, |
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blocks, offs, submit); |
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case 3: |
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/* dma devices do not uniformly understand a single |
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* source pq operation (in contrast to the synchronous |
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* case), so explicitly handle the special case of a 5 disk |
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* array with 2 of 3 data disks missing. |
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*/ |
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return __2data_recov_5(disks, bytes, faila, failb, |
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blocks, offs, submit); |
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default: |
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return __2data_recov_n(disks, bytes, faila, failb, |
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blocks, offs, submit); |
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} |
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} |
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EXPORT_SYMBOL_GPL(async_raid6_2data_recov); |
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|
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/** |
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* async_raid6_datap_recov - asynchronously calculate a data and the 'p' block |
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* @disks: number of disks in the RAID-6 array |
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* @bytes: block size |
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* @faila: failed drive index |
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* @blocks: array of source pointers where the last two entries are p and q |
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* @offs: array of offset for pages in blocks |
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* @submit: submission/completion modifiers |
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*/ |
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struct dma_async_tx_descriptor * |
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async_raid6_datap_recov(int disks, size_t bytes, int faila, |
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struct page **blocks, unsigned int *offs, |
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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 page *p, *q, *dq; |
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unsigned int p_off, q_off, dq_off; |
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u8 coef; |
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enum async_tx_flags flags = submit->flags; |
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dma_async_tx_callback cb_fn = submit->cb_fn; |
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void *cb_param = submit->cb_param; |
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void *scribble = submit->scribble; |
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int good_srcs, good, i; |
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struct page *srcs[2]; |
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unsigned int src_offs[2]; |
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|
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pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); |
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|
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/* if a dma resource is not available or a scribble buffer is not |
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* available punt to the synchronous path. In the 'dma not |
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* available' case be sure to use the scribble buffer to |
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* preserve the content of 'blocks' as the caller intended. |
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*/ |
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if (!async_dma_find_channel(DMA_PQ) || !scribble) { |
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void **ptrs = scribble ? scribble : (void **) blocks; |
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|
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async_tx_quiesce(&submit->depend_tx); |
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for (i = 0; i < disks; i++) |
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if (blocks[i] == NULL) |
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ptrs[i] = (void*)raid6_empty_zero_page; |
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else |
|
ptrs[i] = page_address(blocks[i]) + offs[i]; |
|
|
|
raid6_datap_recov(disks, bytes, faila, ptrs); |
|
|
|
async_tx_sync_epilog(submit); |
|
|
|
return NULL; |
|
} |
|
|
|
good_srcs = 0; |
|
good = -1; |
|
for (i = 0; i < disks-2; i++) { |
|
if (i == faila) |
|
continue; |
|
if (blocks[i]) { |
|
good = i; |
|
good_srcs++; |
|
if (good_srcs > 1) |
|
break; |
|
} |
|
} |
|
BUG_ON(good_srcs == 0); |
|
|
|
p = blocks[disks-2]; |
|
p_off = offs[disks-2]; |
|
q = blocks[disks-1]; |
|
q_off = offs[disks-1]; |
|
|
|
/* Compute syndrome with zero for the missing data page |
|
* Use the dead data page as temporary storage for delta q |
|
*/ |
|
dq = blocks[faila]; |
|
dq_off = offs[faila]; |
|
blocks[faila] = NULL; |
|
blocks[disks-1] = dq; |
|
offs[disks-1] = dq_off; |
|
|
|
/* in the 4-disk case we only need to perform a single source |
|
* multiplication with the one good data block. |
|
*/ |
|
if (good_srcs == 1) { |
|
struct page *g = blocks[good]; |
|
unsigned int g_off = offs[good]; |
|
|
|
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
|
scribble); |
|
tx = async_memcpy(p, g, p_off, g_off, bytes, submit); |
|
|
|
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
|
scribble); |
|
tx = async_mult(dq, dq_off, g, g_off, |
|
raid6_gfexp[good], bytes, submit); |
|
} else { |
|
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
|
scribble); |
|
tx = async_gen_syndrome(blocks, offs, disks, bytes, submit); |
|
} |
|
|
|
/* Restore pointer table */ |
|
blocks[faila] = dq; |
|
offs[faila] = dq_off; |
|
blocks[disks-1] = q; |
|
offs[disks-1] = q_off; |
|
|
|
/* calculate g^{-faila} */ |
|
coef = raid6_gfinv[raid6_gfexp[faila]]; |
|
|
|
srcs[0] = dq; |
|
src_offs[0] = dq_off; |
|
srcs[1] = q; |
|
src_offs[1] = q_off; |
|
init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
|
NULL, NULL, scribble); |
|
tx = async_xor_offs(dq, dq_off, srcs, src_offs, 2, bytes, submit); |
|
|
|
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
|
tx = async_mult(dq, dq_off, dq, dq_off, coef, bytes, submit); |
|
|
|
srcs[0] = p; |
|
src_offs[0] = p_off; |
|
srcs[1] = dq; |
|
src_offs[1] = dq_off; |
|
init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
|
cb_param, scribble); |
|
tx = async_xor_offs(p, p_off, srcs, src_offs, 2, bytes, submit); |
|
|
|
return tx; |
|
} |
|
EXPORT_SYMBOL_GPL(async_raid6_datap_recov); |
|
|
|
MODULE_AUTHOR("Dan Williams <[email protected]>"); |
|
MODULE_DESCRIPTION("asynchronous RAID-6 recovery api"); |
|
MODULE_LICENSE("GPL");
|
|
|