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