/* * Cryptographic API. * * Cipher operations. * * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> * 2002 Adam J. Richter <adam@yggdrasil.com> * 2004 Jean-Luc Cooke <jlcooke@certainkey.com> * * 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. * */ #include <linux/kernel.h> #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/highmem.h> #include <asm/scatterlist.h> #include "internal.h" #include "scatterwalk.h" enum km_type crypto_km_types[] = { KM_USER0, KM_USER1, KM_SOFTIRQ0, KM_SOFTIRQ1, }; static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) { if (out) memcpy(sgdata, buf, nbytes); else memcpy(buf, sgdata, nbytes); } void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg) { unsigned int rest_of_page; walk->sg = sg; walk->page = sg->page; walk->len_this_segment = sg->length; BUG_ON(!sg->length); rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1)); walk->len_this_page = min(sg->length, rest_of_page); walk->offset = sg->offset; } void scatterwalk_map(struct scatter_walk *walk, int out) { walk->data = crypto_kmap(walk->page, out) + walk->offset; } static inline void scatterwalk_unmap(struct scatter_walk *walk, int out) { /* walk->data may be pointing the first byte of the next page; however, we know we transfered at least one byte. So, walk->data - 1 will be a virtual address in the mapped page. */ crypto_kunmap(walk->data - 1, out); } static void scatterwalk_pagedone(struct scatter_walk *walk, int out, unsigned int more) { if (out) flush_dcache_page(walk->page); if (more) { walk->len_this_segment -= walk->len_this_page; if (walk->len_this_segment) { walk->page++; walk->len_this_page = min(walk->len_this_segment, (unsigned)PAGE_CACHE_SIZE); walk->offset = 0; } else scatterwalk_start(walk, sg_next(walk->sg)); } } void scatterwalk_done(struct scatter_walk *walk, int out, int more) { scatterwalk_unmap(walk, out); if (walk->len_this_page == 0 || !more) scatterwalk_pagedone(walk, out, more); } /* * Do not call this unless the total length of all of the fragments * has been verified as multiple of the block size. */ int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out) { while (nbytes > walk->len_this_page) { memcpy_dir(buf, walk->data, walk->len_this_page, out); buf += walk->len_this_page; nbytes -= walk->len_this_page; scatterwalk_unmap(walk, out); scatterwalk_pagedone(walk, out, 1); scatterwalk_map(walk, out); } memcpy_dir(buf, walk->data, nbytes, out); return nbytes; }