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[CRYPTO] scatterwalk: Prepare for block ciphers

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This patch prepares the scatterwalk code for use by the new block cipher
type.

Firstly it halves the size of scatter_walk on 32-bit platforms.  This
is important as we allocate at least two of these objects on the stack
for each block cipher operation.

It also exports the symbols since the block cipher code can be built as
a module.

Finally there is a hack in scatterwalk_unmap that relies on progress
being made.  Unfortunately, for hardware crypto we can't guarantee
progress to be made since the hardware can fail.

So this also gets rid of the hack by not advancing the address returned
by scatterwalk_map.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu
2006-08-12 21:56:17 +10:00
parent f28776a369
commit 5c64097aa0
4 changed files with 88 additions and 83 deletions
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27
crypto/cipher.c
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@ -45,15 +45,10 @@ static unsigned int crypt_slow(const struct cipher_desc *desc,
u8 buffer[bsize * 2 + alignmask];
u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
u8 *dst = src + bsize;
unsigned int n;
n = scatterwalk_copychunks(src, in, bsize, 0);
scatterwalk_advance(in, n);
scatterwalk_copychunks(src, in, bsize, 0);
desc->prfn(desc, dst, src, bsize);
n = scatterwalk_copychunks(dst, out, bsize, 1);
scatterwalk_advance(out, n);
scatterwalk_copychunks(dst, out, bsize, 1);
return bsize;
}
@ -64,12 +59,16 @@ static inline unsigned int crypt_fast(const struct cipher_desc *desc,
unsigned int nbytes, u8 *tmp)
{
u8 *src, *dst;
u8 *real_src, *real_dst;
src = in->data;
dst = scatterwalk_samebuf(in, out) ? src : out->data;
real_src = scatterwalk_map(in, 0);
real_dst = scatterwalk_map(out, 1);
src = real_src;
dst = scatterwalk_samebuf(in, out) ? src : real_dst;
if (tmp) {
memcpy(tmp, in->data, nbytes);
memcpy(tmp, src, nbytes);
src = tmp;
dst = tmp;
}
@ -77,7 +76,10 @@ static inline unsigned int crypt_fast(const struct cipher_desc *desc,
nbytes = desc->prfn(desc, dst, src, nbytes);
if (tmp)
memcpy(out->data, tmp, nbytes);
memcpy(real_dst, tmp, nbytes);
scatterwalk_unmap(real_src, 0);
scatterwalk_unmap(real_dst, 1);
scatterwalk_advance(in, nbytes);
scatterwalk_advance(out, nbytes);
@ -126,9 +128,6 @@ static int crypt(const struct cipher_desc *desc,
tmp = (u8 *)buffer;
}
scatterwalk_map(&walk_in, 0);
scatterwalk_map(&walk_out, 1);
n = scatterwalk_clamp(&walk_in, n);
n = scatterwalk_clamp(&walk_out, n);