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 sg1[num - 1].page_link |= 0x01; 40 } 41 42 static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg) 43 { 44 if (sg_is_last(sg)) 45 return NULL; 46 47 return (++sg)->length ? sg : sg_chain_ptr(sg); 48 } 49 50 static inline void scatterwalk_crypto_chain(struct scatterlist *head, 51 struct scatterlist *sg, 52 int chain, int num) 53 { 54 if (chain) { 55 head->length += sg->length; 56 sg = scatterwalk_sg_next(sg); 57 } 58 59 if (sg) 60 scatterwalk_sg_chain(head, num, sg); 61 else 62 sg_mark_end(head); 63 } 64 65 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in, 66 struct scatter_walk *walk_out) 67 { 68 return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) + 69 (int)(walk_in->offset - walk_out->offset)); 70 } 71 72 static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk) 73 { 74 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset; 75 unsigned int len_this_page = offset_in_page(~walk->offset) + 1; 76 return len_this_page > len ? len : len_this_page; 77 } 78 79 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk, 80 unsigned int nbytes) 81 { 82 unsigned int len_this_page = scatterwalk_pagelen(walk); 83 return nbytes > len_this_page ? len_this_page : nbytes; 84 } 85 86 static inline void scatterwalk_advance(struct scatter_walk *walk, 87 unsigned int nbytes) 88 { 89 walk->offset += nbytes; 90 } 91 92 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk, 93 unsigned int alignmask) 94 { 95 return !(walk->offset & alignmask); 96 } 97 98 static inline struct page *scatterwalk_page(struct scatter_walk *walk) 99 { 100 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT); 101 } 102 103 static inline void scatterwalk_unmap(void *vaddr) 104 { 105 kunmap_atomic(vaddr); 106 } 107 108 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg); 109 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, 110 size_t nbytes, int out); 111 void *scatterwalk_map(struct scatter_walk *walk); 112 void scatterwalk_done(struct scatter_walk *walk, int out, int more); 113 114 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, 115 unsigned int start, unsigned int nbytes, int out); 116 117 int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes); 118 119 #endif /* _CRYPTO_SCATTERWALK_H */ 120