506 lines
14 KiB
C
506 lines
14 KiB
C
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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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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*
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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/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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static struct dma_async_tx_descriptor *
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async_sum_product(struct page *dest, struct page **srcs, 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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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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dma_addr_t dma_dest[2];
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dma_addr_t dma_src[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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dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
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dma_src[0] = dma_map_page(dev, srcs[0], 0, len, DMA_TO_DEVICE);
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dma_src[1] = dma_map_page(dev, srcs[1], 0, len, DMA_TO_DEVICE);
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tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 2, coef,
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len, dma_flags);
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if (tx) {
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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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dma_unmap_page(dev, dma_dest[1], len, DMA_BIDIRECTIONAL);
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dma_unmap_page(dev, dma_src[0], len, DMA_TO_DEVICE);
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dma_unmap_page(dev, dma_src[1], len, DMA_TO_DEVICE);
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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]);
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b = page_address(srcs[1]);
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c = page_address(dest);
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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, struct page *src, 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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const u8 *qmul; /* Q multiplier table */
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u8 *d, *s;
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if (dma) {
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dma_addr_t dma_dest[2];
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dma_addr_t dma_src[1];
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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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dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
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dma_src[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE);
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tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 1, &coef,
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len, dma_flags);
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if (tx) {
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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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dma_unmap_page(dev, dma_dest[1], len, DMA_BIDIRECTIONAL);
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dma_unmap_page(dev, dma_src[0], len, DMA_TO_DEVICE);
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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);
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s = page_address(src);
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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, 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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struct page *srcs[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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q = blocks[disks-1];
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a = blocks[faila];
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b = blocks[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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srcs[1] = q;
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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, srcs, coef, bytes, submit);
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/* Dy = P+Pxy+Dx */
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srcs[0] = p;
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srcs[1] = b;
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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(a, srcs, 0, 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, 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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struct page *srcs[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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q = blocks[disks-1];
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g = blocks[good];
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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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dq = blocks[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, 0, 0, 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, g, raid6_gfexp[good], bytes, submit);
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/* compute P + Pxy */
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srcs[0] = dp;
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srcs[1] = p;
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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(dp, srcs, 0, 2, bytes, submit);
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/* compute Q + Qxy */
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srcs[0] = dq;
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srcs[1] = q;
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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(dq, srcs, 0, 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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srcs[1] = dq;
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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, srcs, coef, bytes, submit);
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/* Dy = P+Pxy+Dx */
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srcs[0] = dp;
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srcs[1] = dq;
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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(dp, srcs, 0, 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, 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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struct page *srcs[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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q = blocks[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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blocks[faila] = NULL;
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blocks[disks-2] = dp;
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dq = blocks[failb];
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blocks[failb] = NULL;
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blocks[disks-1] = dq;
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init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
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tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
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/* Restore pointer table */
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blocks[faila] = dp;
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blocks[failb] = dq;
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blocks[disks-2] = p;
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blocks[disks-1] = q;
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/* compute P + Pxy */
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srcs[0] = dp;
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srcs[1] = p;
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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(dp, srcs, 0, 2, bytes, submit);
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/* compute Q + Qxy */
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srcs[0] = dq;
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srcs[1] = q;
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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(dq, srcs, 0, 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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srcs[1] = dq;
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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, srcs, coef, bytes, submit);
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/* Dy = P+Pxy+Dx */
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srcs[0] = dp;
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srcs[1] = dq;
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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(dp, srcs, 0, 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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* @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, 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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/* 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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|
*/
|
||
|
|
if (!async_dma_find_channel(DMA_PQ) || !scribble) {
|
||
|
|
void **ptrs = scribble ? scribble : (void **) blocks;
|
||
|
|
|
||
|
|
async_tx_quiesce(&submit->depend_tx);
|
||
|
|
for (i = 0; i < disks; i++)
|
||
|
|
if (blocks[i] == NULL)
|
||
|
|
ptrs[i] = (void *) raid6_empty_zero_page;
|
||
|
|
else
|
||
|
|
ptrs[i] = page_address(blocks[i]);
|
||
|
|
|
||
|
|
raid6_2data_recov(disks, bytes, faila, failb, ptrs);
|
||
|
|
|
||
|
|
async_tx_sync_epilog(submit);
|
||
|
|
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
non_zero_srcs = 0;
|
||
|
|
for (i = 0; i < disks-2 && non_zero_srcs < 4; i++)
|
||
|
|
if (blocks[i])
|
||
|
|
non_zero_srcs++;
|
||
|
|
switch (non_zero_srcs) {
|
||
|
|
case 0:
|
||
|
|
case 1:
|
||
|
|
/* There must be at least 2 sources - the failed devices. */
|
||
|
|
BUG();
|
||
|
|
|
||
|
|
case 2:
|
||
|
|
/* dma devices do not uniformly understand a zero source pq
|
||
|
|
* operation (in contrast to the synchronous case), so
|
||
|
|
* explicitly handle the special case of a 4 disk array with
|
||
|
|
* both data disks missing.
|
||
|
|
*/
|
||
|
|
return __2data_recov_4(disks, bytes, faila, failb, blocks, submit);
|
||
|
|
case 3:
|
||
|
|
/* dma devices do not uniformly understand a single
|
||
|
|
* source pq operation (in contrast to the synchronous
|
||
|
|
* case), so explicitly handle the special case of a 5 disk
|
||
|
|
* array with 2 of 3 data disks missing.
|
||
|
|
*/
|
||
|
|
return __2data_recov_5(disks, bytes, faila, failb, blocks, submit);
|
||
|
|
default:
|
||
|
|
return __2data_recov_n(disks, bytes, faila, failb, blocks, submit);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(async_raid6_2data_recov);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* async_raid6_datap_recov - asynchronously calculate a data and the 'p' block
|
||
|
|
* @disks: number of disks in the RAID-6 array
|
||
|
|
* @bytes: block size
|
||
|
|
* @faila: failed drive index
|
||
|
|
* @blocks: array of source pointers where the last two entries are p and q
|
||
|
|
* @submit: submission/completion modifiers
|
||
|
|
*/
|
||
|
|
struct dma_async_tx_descriptor *
|
||
|
|
async_raid6_datap_recov(int disks, size_t bytes, int faila,
|
||
|
|
struct page **blocks, struct async_submit_ctl *submit)
|
||
|
|
{
|
||
|
|
struct dma_async_tx_descriptor *tx = NULL;
|
||
|
|
struct page *p, *q, *dq;
|
||
|
|
u8 coef;
|
||
|
|
enum async_tx_flags flags = submit->flags;
|
||
|
|
dma_async_tx_callback cb_fn = submit->cb_fn;
|
||
|
|
void *cb_param = submit->cb_param;
|
||
|
|
void *scribble = submit->scribble;
|
||
|
|
int good_srcs, good, i;
|
||
|
|
struct page *srcs[2];
|
||
|
|
|
||
|
|
pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
|
||
|
|
|
||
|
|
/* if a dma resource is not available or a scribble buffer is not
|
||
|
|
* available punt to the synchronous path. In the 'dma not
|
||
|
|
* available' case be sure to use the scribble buffer to
|
||
|
|
* preserve the content of 'blocks' as the caller intended.
|
||
|
|
*/
|
||
|
|
if (!async_dma_find_channel(DMA_PQ) || !scribble) {
|
||
|
|
void **ptrs = scribble ? scribble : (void **) blocks;
|
||
|
|
|
||
|
|
async_tx_quiesce(&submit->depend_tx);
|
||
|
|
for (i = 0; i < disks; i++)
|
||
|
|
if (blocks[i] == NULL)
|
||
|
|
ptrs[i] = (void*)raid6_empty_zero_page;
|
||
|
|
else
|
||
|
|
ptrs[i] = page_address(blocks[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];
|
||
|
|
q = blocks[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];
|
||
|
|
blocks[faila] = NULL;
|
||
|
|
blocks[disks-1] = dq;
|
||
|
|
|
||
|
|
/* 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];
|
||
|
|
|
||
|
|
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
|
||
|
|
scribble);
|
||
|
|
tx = async_memcpy(p, g, 0, 0, bytes, submit);
|
||
|
|
|
||
|
|
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
|
||
|
|
scribble);
|
||
|
|
tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
|
||
|
|
} else {
|
||
|
|
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
|
||
|
|
scribble);
|
||
|
|
tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Restore pointer table */
|
||
|
|
blocks[faila] = dq;
|
||
|
|
blocks[disks-1] = q;
|
||
|
|
|
||
|
|
/* calculate g^{-faila} */
|
||
|
|
coef = raid6_gfinv[raid6_gfexp[faila]];
|
||
|
|
|
||
|
|
srcs[0] = dq;
|
||
|
|
srcs[1] = q;
|
||
|
|
init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
|
||
|
|
NULL, NULL, scribble);
|
||
|
|
tx = async_xor(dq, srcs, 0, 2, bytes, submit);
|
||
|
|
|
||
|
|
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
|
||
|
|
tx = async_mult(dq, dq, coef, bytes, submit);
|
||
|
|
|
||
|
|
srcs[0] = p;
|
||
|
|
srcs[1] = dq;
|
||
|
|
init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
|
||
|
|
cb_param, scribble);
|
||
|
|
tx = async_xor(p, srcs, 0, 2, bytes, submit);
|
||
|
|
|
||
|
|
return tx;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(async_raid6_datap_recov);
|
||
|
|
|
||
|
|
MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>");
|
||
|
|
MODULE_DESCRIPTION("asynchronous RAID-6 recovery api");
|
||
|
|
MODULE_LICENSE("GPL");
|