static inline unsigned int crypt_fast(const struct cipher_desc *desc,
struct scatter_walk *in,
struct scatter_walk *out,
unsigned int nbytes, u8 *tmp)
{
u8 *src, *dst;
src = in->data;
dst = scatterwalk_samebuf(in, out) ? src : out->data;
if (tmp) {
memcpy(tmp, in->data, nbytes);
src = tmp;
dst = tmp;
}
nbytes = desc->prfn(desc, dst, src, nbytes);
if (tmp)
memcpy(out->data, tmp, nbytes);
scatterwalk_advance(in, nbytes);
scatterwalk_advance(out, nbytes);
return nbytes;
}
/*
* Generic encrypt/decrypt wrapper for ciphers, handles operations across
* multiple page boundaries by using temporary blocks. In user context,
* the kernel is given a chance to schedule us once per block.
*/
static int crypt(struct crypto_tfm *tfm,
struct scatterlist *dst,
struct scatterlist *src,
unsigned int nbytes, cryptfn_t crfn,
procfn_t prfn, int enc, void *info)
{
struct scatter_walk walk_in, walk_out;
const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
u8 tmp_src[bsize];
u8 tmp_dst[bsize];
if (!nbytes)
return 0;
if (nbytes % bsize) {
tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
return -EINVAL;
}
scatterwalk_start(&walk_in, src);
scatterwalk_start(&walk_out, dst);
for(;;) {
u8 *src_p, *dst_p;
int in_place;
scatterwalk_map(&walk_in);
scatterwalk_map(&walk_out);
src_p = scatterwalk_whichbuf(&walk_in, bsize, tmp_src);
dst_p = scatterwalk_whichbuf(&walk_out, bsize, tmp_dst);
in_place = scatterwalk_samebuf(&walk_in, &walk_out,
src_p, dst_p);
nbytes -= bsize;
scatterwalk_copychunks(src_p, &walk_in, bsize, 0);
prfn(tfm, dst_p, src_p, crfn, enc, info, in_place);
scatterwalk_done(&walk_in, nbytes);
scatterwalk_copychunks(dst_p, &walk_out, bsize, 1);
scatterwalk_done(&walk_out, nbytes);
if (!nbytes)
return 0;
crypto_yield(tfm);
}
}
