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
);
58 flush_dcache_page(page
);
62 walk
->offset
+= PAGE_SIZE
- 1;
63 walk
->offset
&= PAGE_MASK
;
64 if (walk
->offset
>= walk
->sg
->offset
+ walk
->sg
->length
)
65 scatterwalk_start(walk
, sg_next(walk
->sg
));
69 void scatterwalk_done(struct scatter_walk
*walk
, int out
, int more
)
71 if (!(scatterwalk_pagelen(walk
) & (PAGE_SIZE
- 1)) || !more
)
72 scatterwalk_pagedone(walk
, out
, more
);
74 EXPORT_SYMBOL_GPL(scatterwalk_done
);
76 void scatterwalk_copychunks(void *buf
, struct scatter_walk
*walk
,
77 size_t nbytes
, int out
)
80 unsigned int len_this_page
= scatterwalk_pagelen(walk
);
83 if (len_this_page
> nbytes
)
84 len_this_page
= nbytes
;
86 vaddr
= scatterwalk_map(walk
);
87 memcpy_dir(buf
, vaddr
, len_this_page
, out
);
88 scatterwalk_unmap(vaddr
);
90 scatterwalk_advance(walk
, len_this_page
);
92 if (nbytes
== len_this_page
)
96 nbytes
-= len_this_page
;
98 scatterwalk_pagedone(walk
, out
, 1);
101 EXPORT_SYMBOL_GPL(scatterwalk_copychunks
);
103 void scatterwalk_map_and_copy(void *buf
, struct scatterlist
*sg
,
104 unsigned int start
, unsigned int nbytes
, int out
)
106 struct scatter_walk walk
;
107 unsigned int offset
= 0;
113 scatterwalk_start(&walk
, sg
);
115 if (start
< offset
+ sg
->length
)
118 offset
+= sg
->length
;
122 scatterwalk_advance(&walk
, start
- offset
);
123 scatterwalk_copychunks(buf
, &walk
, nbytes
, out
);
124 scatterwalk_done(&walk
, out
, 0);
126 EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy
);
128 int scatterwalk_bytes_sglen(struct scatterlist
*sg
, int num_bytes
)
130 int offset
= 0, n
= 0;
132 /* num_bytes is too small */
133 if (num_bytes
< sg
->length
)
137 offset
+= sg
->length
;
141 /* num_bytes is too large */
142 if (unlikely(!sg
&& (num_bytes
< offset
)))
144 } while (sg
&& (num_bytes
> offset
));
148 EXPORT_SYMBOL_GPL(scatterwalk_bytes_sglen
);