diff options
| -rw-r--r-- | crypto/scatterwalk.c | 22 | ||||
| -rw-r--r-- | crypto/scatterwalk.h | 3 |
2 files changed, 25 insertions, 0 deletions
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c index 81afd1790a1..e93a8f6f35d 100644 --- a/crypto/scatterwalk.c +++ b/crypto/scatterwalk.c @@ -107,3 +107,25 @@ void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, } } EXPORT_SYMBOL_GPL(scatterwalk_copychunks); + +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; + + for (;;) { + scatterwalk_start(&walk, sg); + + if (start < offset + sg->length) + break; + + offset += sg->length; + sg = sg_next(sg); + } + + scatterwalk_advance(&walk, start - offset); + scatterwalk_copychunks(buf, &walk, nbytes, out); + scatterwalk_done(&walk, out, 0); +} +EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy); diff --git a/crypto/scatterwalk.h b/crypto/scatterwalk.h index f1592cc2d0f..500a220ad90 100644 --- a/crypto/scatterwalk.h +++ b/crypto/scatterwalk.h @@ -74,4 +74,7 @@ void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, void *scatterwalk_map(struct scatter_walk *walk, int out); void scatterwalk_done(struct scatter_walk *walk, int out, int more); +void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, + unsigned int start, unsigned int nbytes, int out); + #endif /* _CRYPTO_SCATTERWALK_H */ |