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- /*
- * Cryptographic scatter and gather helpers.
- *
- * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
- * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
- * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
- * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
- *
- * 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.
- *
- */
- #ifndef _CRYPTO_SCATTERWALK_H
- #define _CRYPTO_SCATTERWALK_H
- #include <crypto/algapi.h>
- #include <linux/highmem.h>
- #include <linux/kernel.h>
- #include <linux/scatterlist.h>
- static inline void scatterwalk_crypto_chain(struct scatterlist *head,
- struct scatterlist *sg,
- int chain, int num)
- {
- if (chain) {
- head->length += sg->length;
- sg = sg_next(sg);
- }
- if (sg)
- sg_chain(head, num, sg);
- else
- sg_mark_end(head);
- }
- static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
- struct scatter_walk *walk_out)
- {
- return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
- (int)(walk_in->offset - walk_out->offset));
- }
- static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
- {
- unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
- unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
- return len_this_page > len ? len : len_this_page;
- }
- static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
- unsigned int nbytes)
- {
- unsigned int len_this_page = scatterwalk_pagelen(walk);
- return nbytes > len_this_page ? len_this_page : nbytes;
- }
- static inline void scatterwalk_advance(struct scatter_walk *walk,
- unsigned int nbytes)
- {
- walk->offset += nbytes;
- }
- static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
- unsigned int alignmask)
- {
- return !(walk->offset & alignmask);
- }
- static inline struct page *scatterwalk_page(struct scatter_walk *walk)
- {
- return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
- }
- static inline void scatterwalk_unmap(void *vaddr)
- {
- kunmap_atomic(vaddr);
- }
- static inline void scatterwalk_start(struct scatter_walk *walk,
- struct scatterlist *sg)
- {
- walk->sg = sg;
- walk->offset = sg->offset;
- }
- static inline void *scatterwalk_map(struct scatter_walk *walk)
- {
- return kmap_atomic(scatterwalk_page(walk)) +
- offset_in_page(walk->offset);
- }
- static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
- unsigned int more)
- {
- if (out) {
- struct page *page;
- page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
- /* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
- * PageSlab cannot be optimised away per se due to
- * use of volatile pointer.
- */
- if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
- flush_dcache_page(page);
- }
- if (more && walk->offset >= walk->sg->offset + walk->sg->length)
- scatterwalk_start(walk, sg_next(walk->sg));
- }
- static inline void scatterwalk_done(struct scatter_walk *walk, int out,
- int more)
- {
- if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
- !(walk->offset & (PAGE_SIZE - 1)))
- scatterwalk_pagedone(walk, out, more);
- }
- void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
- size_t nbytes, int out);
- void *scatterwalk_map(struct scatter_walk *walk);
- void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
- unsigned int start, unsigned int nbytes, int out);
- struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
- struct scatterlist *src,
- unsigned int len);
- #endif /* _CRYPTO_SCATTERWALK_H */
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