/*
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* Copyright (c) 2011 Maxim Levitsky
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*
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* This file is part of linux cryptodev.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <crypto/scatterwalk.h>
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#include <linux/scatterlist.h>
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#include "util.h"
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/* These were taken from Maxim Levitsky's patch to lkml.
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*/
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struct scatterlist *cryptodev_sg_advance(struct scatterlist *sg, int consumed)
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{
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while (consumed >= sg->length) {
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consumed -= sg->length;
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sg = sg_next(sg);
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if (!sg)
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break;
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}
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WARN_ON(!sg && consumed);
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if (!sg)
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return NULL;
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sg->offset += consumed;
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sg->length -= consumed;
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if (sg->offset >= PAGE_SIZE) {
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struct page *page =
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nth_page(sg_page(sg), sg->offset / PAGE_SIZE);
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sg_set_page(sg, page, sg->length, sg->offset % PAGE_SIZE);
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}
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return sg;
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}
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/**
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* cryptodev_sg_copy - copies sg entries from sg_from to sg_to, such
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* as sg_to covers first 'len' bytes from sg_from.
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*/
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int cryptodev_sg_copy(struct scatterlist *sg_from, struct scatterlist *sg_to, int len)
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{
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while (len > sg_from->length) {
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len -= sg_from->length;
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sg_set_page(sg_to, sg_page(sg_from),
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sg_from->length, sg_from->offset);
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sg_to = sg_next(sg_to);
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sg_from = sg_next(sg_from);
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if (len && (!sg_from || !sg_to))
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return -ENOMEM;
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}
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if (len)
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sg_set_page(sg_to, sg_page(sg_from),
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len, sg_from->offset);
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sg_mark_end(sg_to);
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return 0;
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}
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