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 crypto_yield(u32 flags) 29 { 30 if (flags & CRYPTO_TFM_REQ_MAY_SLEEP) 31 cond_resched(); 32 } 33 34 static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num, 35 struct scatterlist *sg2) 36 { 37 sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0); 38 sg1[num - 1].page_link &= ~0x02; 39 } 40 41 static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg) 42 { 43 if (sg_is_last(sg)) 44 return NULL; 45 46 return (++sg)->length ? sg : (void *)sg_page(sg); 47 } 48 49 static inline void scatterwalk_crypto_chain(struct scatterlist *head, 50 struct scatterlist *sg, 51 int chain, int num) 52 { 53 if (chain) { 54 head->length += sg->length; 55 sg = scatterwalk_sg_next(sg); 56 } 57 58 if (sg) 59 scatterwalk_sg_chain(head, num, sg); 60 else 61 sg_mark_end(head); 62 } 63 64 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in, 65 struct scatter_walk *walk_out) 66 { 67 return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) + 68 (int)(walk_in->offset - walk_out->offset)); 69 } 70 71 static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk) 72 { 73 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset; 74 unsigned int len_this_page = offset_in_page(~walk->offset) + 1; 75 return len_this_page > len ? len : len_this_page; 76 } 77 78 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk, 79 unsigned int nbytes) 80 { 81 unsigned int len_this_page = scatterwalk_pagelen(walk); 82 return nbytes > len_this_page ? len_this_page : nbytes; 83 } 84 85 static inline void scatterwalk_advance(struct scatter_walk *walk, 86 unsigned int nbytes) 87 { 88 walk->offset += nbytes; 89 } 90 91 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk, 92 unsigned int alignmask) 93 { 94 return !(walk->offset & alignmask); 95 } 96 97 static inline struct page *scatterwalk_page(struct scatter_walk *walk) 98 { 99 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT); 100 } 101 102 static inline void scatterwalk_unmap(void *vaddr) 103 { 104 kunmap_atomic(vaddr); 105 } 106 107 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg); 108 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, 109 size_t nbytes, int out); 110 void *scatterwalk_map(struct scatter_walk *walk); 111 void scatterwalk_done(struct scatter_walk *walk, int out, int more); 112 113 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, 114 unsigned int start, unsigned int nbytes, int out); 115 116 int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes); 117 118 #endif /* _CRYPTO_SCATTERWALK_H */ 119