scatterwalk.h 3.7 KB

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  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. #ifndef _CRYPTO_SCATTERWALK_H
  16. #define _CRYPTO_SCATTERWALK_H
  17. #include <crypto/algapi.h>
  18. #include <linux/highmem.h>
  19. #include <linux/kernel.h>
  20. #include <linux/scatterlist.h>
  21. static inline void scatterwalk_crypto_chain(struct scatterlist *head,
  22. struct scatterlist *sg,
  23. int chain, int num)
  24. {
  25. if (chain) {
  26. head->length += sg->length;
  27. sg = sg_next(sg);
  28. }
  29. if (sg)
  30. sg_chain(head, num, sg);
  31. else
  32. sg_mark_end(head);
  33. }
  34. static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
  35. struct scatter_walk *walk_out)
  36. {
  37. return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
  38. (int)(walk_in->offset - walk_out->offset));
  39. }
  40. static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
  41. {
  42. unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
  43. unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
  44. return len_this_page > len ? len : len_this_page;
  45. }
  46. static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
  47. unsigned int nbytes)
  48. {
  49. unsigned int len_this_page = scatterwalk_pagelen(walk);
  50. return nbytes > len_this_page ? len_this_page : nbytes;
  51. }
  52. static inline void scatterwalk_advance(struct scatter_walk *walk,
  53. unsigned int nbytes)
  54. {
  55. walk->offset += nbytes;
  56. }
  57. static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  58. unsigned int alignmask)
  59. {
  60. return !(walk->offset & alignmask);
  61. }
  62. static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  63. {
  64. return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  65. }
  66. static inline void scatterwalk_unmap(void *vaddr)
  67. {
  68. kunmap_atomic(vaddr);
  69. }
  70. static inline void scatterwalk_start(struct scatter_walk *walk,
  71. struct scatterlist *sg)
  72. {
  73. walk->sg = sg;
  74. walk->offset = sg->offset;
  75. }
  76. static inline void *scatterwalk_map(struct scatter_walk *walk)
  77. {
  78. return kmap_atomic(scatterwalk_page(walk)) +
  79. offset_in_page(walk->offset);
  80. }
  81. static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
  82. unsigned int more)
  83. {
  84. if (out) {
  85. struct page *page;
  86. page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
  87. /* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
  88. * PageSlab cannot be optimised away per se due to
  89. * use of volatile pointer.
  90. */
  91. if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
  92. flush_dcache_page(page);
  93. }
  94. if (more && walk->offset >= walk->sg->offset + walk->sg->length)
  95. scatterwalk_start(walk, sg_next(walk->sg));
  96. }
  97. static inline void scatterwalk_done(struct scatter_walk *walk, int out,
  98. int more)
  99. {
  100. if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
  101. !(walk->offset & (PAGE_SIZE - 1)))
  102. scatterwalk_pagedone(walk, out, more);
  103. }
  104. void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
  105. size_t nbytes, int out);
  106. void *scatterwalk_map(struct scatter_walk *walk);
  107. void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
  108. unsigned int start, unsigned int nbytes, int out);
  109. struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
  110. struct scatterlist *src,
  111. unsigned int len);
  112. #endif /* _CRYPTO_SCATTERWALK_H */