diff options
Diffstat (limited to 'crypto/scatterwalk.c')
-rw-r--r-- | crypto/scatterwalk.c | 38 |
1 files changed, 28 insertions, 10 deletions
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c index 3bd749c..8690324 100644 --- a/crypto/scatterwalk.c +++ b/crypto/scatterwalk.c @@ -104,22 +104,18 @@ void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, unsigned int start, unsigned int nbytes, int out) { struct scatter_walk walk; - unsigned int offset = 0; + struct scatterlist tmp[2]; if (!nbytes) return; - for (;;) { - scatterwalk_start(&walk, sg); - - if (start < offset + sg->length) - break; + sg = scatterwalk_ffwd(tmp, sg, start); - offset += sg->length; - sg = sg_next(sg); - } + if (sg_page(sg) == virt_to_page(buf) && + sg->offset == offset_in_page(buf)) + return; - scatterwalk_advance(&walk, start - offset); + scatterwalk_start(&walk, sg); scatterwalk_copychunks(buf, &walk, nbytes, out); scatterwalk_done(&walk, out, 0); } @@ -146,3 +142,25 @@ int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes) return n; } EXPORT_SYMBOL_GPL(scatterwalk_bytes_sglen); + +struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2], + struct scatterlist *src, + unsigned int len) +{ + for (;;) { + if (!len) + return src; + + if (src->length > len) + break; + + len -= src->length; + src = sg_next(src); + } + + sg_set_page(dst, sg_page(src), src->length - len, src->offset + len); + scatterwalk_crypto_chain(dst, sg_next(src), 0, 2); + + return dst; +} +EXPORT_SYMBOL_GPL(scatterwalk_ffwd); |