1 /* 2 * Cryptographic scatter and gather helpers. 3 * 4 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> 5 * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com> 6 * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com> 7 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by the Free 11 * Software Foundation; either version 2 of the License, or (at your option) 12 * any later version. 13 * 14 */ 15 16 #ifndef _CRYPTO_SCATTERWALK_H 17 #define _CRYPTO_SCATTERWALK_H 18 19 #include <asm/kmap_types.h> 20 #include <crypto/algapi.h> 21 #include <linux/hardirq.h> 22 #include <linux/highmem.h> 23 #include <linux/kernel.h> 24 #include <linux/mm.h> 25 #include <linux/scatterlist.h> 26 #include <linux/sched.h> 27 28 static inline void scatterwalk_crypto_chain(struct scatterlist *head, 29 struct scatterlist *sg, 30 int chain, int num) 31 { 32 if (chain) { 33 head->length += sg->length; 34 sg = sg_next(sg); 35 } 36 37 if (sg) 38 sg_chain(head, num, sg); 39 else 40 sg_mark_end(head); 41 } 42 43 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in, 44 struct scatter_walk *walk_out) 45 { 46 return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) + 47 (int)(walk_in->offset - walk_out->offset)); 48 } 49 50 static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk) 51 { 52 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset; 53 unsigned int len_this_page = offset_in_page(~walk->offset) + 1; 54 return len_this_page > len ? len : len_this_page; 55 } 56 57 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk, 58 unsigned int nbytes) 59 { 60 unsigned int len_this_page = scatterwalk_pagelen(walk); 61 return nbytes > len_this_page ? len_this_page : nbytes; 62 } 63 64 static inline void scatterwalk_advance(struct scatter_walk *walk, 65 unsigned int nbytes) 66 { 67 walk->offset += nbytes; 68 } 69 70 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk, 71 unsigned int alignmask) 72 { 73 return !(walk->offset & alignmask); 74 } 75 76 static inline struct page *scatterwalk_page(struct scatter_walk *walk) 77 { 78 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT); 79 } 80 81 static inline void scatterwalk_unmap(void *vaddr) 82 { 83 kunmap_atomic(vaddr); 84 } 85 86 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg); 87 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, 88 size_t nbytes, int out); 89 void *scatterwalk_map(struct scatter_walk *walk); 90 void scatterwalk_done(struct scatter_walk *walk, int out, int more); 91 92 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, 93 unsigned int start, unsigned int nbytes, int out); 94 95 int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes); 96 97 struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2], 98 struct scatterlist *src, 99 unsigned int len); 100 101 #endif /* _CRYPTO_SCATTERWALK_H */ 102