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_sg_chain(struct scatterlist *sg1, int num, 29 struct scatterlist *sg2) 30 { 31 sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0); 32 sg1[num - 1].page_link &= ~0x02; 33 sg1[num - 1].page_link |= 0x01; 34 } 35 36 static inline void scatterwalk_crypto_chain(struct scatterlist *head, 37 struct scatterlist *sg, 38 int chain, int num) 39 { 40 if (chain) { 41 head->length += sg->length; 42 sg = sg_next(sg); 43 } 44 45 if (sg) 46 scatterwalk_sg_chain(head, num, sg); 47 else 48 sg_mark_end(head); 49 } 50 51 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in, 52 struct scatter_walk *walk_out) 53 { 54 return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) + 55 (int)(walk_in->offset - walk_out->offset)); 56 } 57 58 static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk) 59 { 60 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset; 61 unsigned int len_this_page = offset_in_page(~walk->offset) + 1; 62 return len_this_page > len ? len : len_this_page; 63 } 64 65 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk, 66 unsigned int nbytes) 67 { 68 unsigned int len_this_page = scatterwalk_pagelen(walk); 69 return nbytes > len_this_page ? len_this_page : nbytes; 70 } 71 72 static inline void scatterwalk_advance(struct scatter_walk *walk, 73 unsigned int nbytes) 74 { 75 walk->offset += nbytes; 76 } 77 78 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk, 79 unsigned int alignmask) 80 { 81 return !(walk->offset & alignmask); 82 } 83 84 static inline struct page *scatterwalk_page(struct scatter_walk *walk) 85 { 86 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT); 87 } 88 89 static inline void scatterwalk_unmap(void *vaddr) 90 { 91 kunmap_atomic(vaddr); 92 } 93 94 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg); 95 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, 96 size_t nbytes, int out); 97 void *scatterwalk_map(struct scatter_walk *walk); 98 void scatterwalk_done(struct scatter_walk *walk, int out, int more); 99 100 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, 101 unsigned int start, unsigned int nbytes, int out); 102 103 int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes); 104 105 #endif /* _CRYPTO_SCATTERWALK_H */ 106