6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7 * 2002 Adam J. Richter <adam@yggdrasil.com>
8 * 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
17 #include <crypto/scatterwalk.h>
18 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/pagemap.h>
22 #include <linux/highmem.h>
23 #include <linux/scatterlist.h>
25 static inline void memcpy_dir(void *buf
, void *sgdata
, size_t nbytes
, int out
)
27 void *src
= out
? buf
: sgdata
;
28 void *dst
= out
? sgdata
: buf
;
30 memcpy(dst
, src
, nbytes
);
33 void scatterwalk_start(struct scatter_walk
*walk
, struct scatterlist
*sg
)
39 walk
->offset
= sg
->offset
;
41 EXPORT_SYMBOL_GPL(scatterwalk_start
);
43 void *scatterwalk_map(struct scatter_walk
*walk
)
45 return kmap_atomic(scatterwalk_page(walk
)) +
46 offset_in_page(walk
->offset
);
48 EXPORT_SYMBOL_GPL(scatterwalk_map
);
50 static void scatterwalk_pagedone(struct scatter_walk
*walk
, int out
,
56 page
= sg_page(walk
->sg
) + ((walk
->offset
- 1) >> PAGE_SHIFT
);
57 /* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
58 * PageSlab cannot be optimised away per se due to
59 * use of volatile pointer.
61 if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
&& !PageSlab(page
))
62 flush_dcache_page(page
);
66 walk
->offset
+= PAGE_SIZE
- 1;
67 walk
->offset
&= PAGE_MASK
;
68 if (walk
->offset
>= walk
->sg
->offset
+ walk
->sg
->length
)
69 scatterwalk_start(walk
, sg_next(walk
->sg
));
73 void scatterwalk_done(struct scatter_walk
*walk
, int out
, int more
)
75 if (!more
|| walk
->offset
>= walk
->sg
->offset
+ walk
->sg
->length
||
76 !(walk
->offset
& (PAGE_SIZE
- 1)))
77 scatterwalk_pagedone(walk
, out
, more
);
79 EXPORT_SYMBOL_GPL(scatterwalk_done
);
81 void scatterwalk_copychunks(void *buf
, struct scatter_walk
*walk
,
82 size_t nbytes
, int out
)
85 unsigned int len_this_page
= scatterwalk_pagelen(walk
);
88 if (len_this_page
> nbytes
)
89 len_this_page
= nbytes
;
92 vaddr
= scatterwalk_map(walk
);
93 memcpy_dir(buf
, vaddr
, len_this_page
, out
);
94 scatterwalk_unmap(vaddr
);
97 scatterwalk_advance(walk
, len_this_page
);
99 if (nbytes
== len_this_page
)
102 buf
+= len_this_page
;
103 nbytes
-= len_this_page
;
105 scatterwalk_pagedone(walk
, out
& 1, 1);
108 EXPORT_SYMBOL_GPL(scatterwalk_copychunks
);
110 void scatterwalk_map_and_copy(void *buf
, struct scatterlist
*sg
,
111 unsigned int start
, unsigned int nbytes
, int out
)
113 struct scatter_walk walk
;
114 struct scatterlist tmp
[2];
119 sg
= scatterwalk_ffwd(tmp
, sg
, start
);
121 if (sg_page(sg
) == virt_to_page(buf
) &&
122 sg
->offset
== offset_in_page(buf
))
125 scatterwalk_start(&walk
, sg
);
126 scatterwalk_copychunks(buf
, &walk
, nbytes
, out
);
127 scatterwalk_done(&walk
, out
, 0);
129 EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy
);
131 struct scatterlist
*scatterwalk_ffwd(struct scatterlist dst
[2],
132 struct scatterlist
*src
,
139 if (src
->length
> len
)
146 sg_init_table(dst
, 2);
147 sg_set_page(dst
, sg_page(src
), src
->length
- len
, src
->offset
+ len
);
148 scatterwalk_crypto_chain(dst
, sg_next(src
), 0, 2);
152 EXPORT_SYMBOL_GPL(scatterwalk_ffwd
);