diff options
| -rw-r--r-- | crypto/scatterwalk.c | 22 | ||||
| -rw-r--r-- | include/crypto/scatterwalk.h | 2 |
2 files changed, 24 insertions, 0 deletions
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c index 7281b8a93ad3..79ca2278c2a3 100644 --- a/crypto/scatterwalk.c +++ b/crypto/scatterwalk.c @@ -124,3 +124,25 @@ void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, scatterwalk_done(&walk, out, 0); } EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy); + +int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes) +{ + int offset = 0, n = 0; + + /* num_bytes is too small */ + if (num_bytes < sg->length) + return -1; + + do { + offset += sg->length; + n++; + sg = scatterwalk_sg_next(sg); + + /* num_bytes is too large */ + if (unlikely(!sg && (num_bytes < offset))) + return -1; + } while (sg && (num_bytes > offset)); + + return n; +} +EXPORT_SYMBOL_GPL(scatterwalk_bytes_sglen); diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h index 3744d2a642df..13621cc8cf4c 100644 --- a/include/crypto/scatterwalk.h +++ b/include/crypto/scatterwalk.h @@ -113,4 +113,6 @@ 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); +int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes); + #endif /* _CRYPTO_SCATTERWALK_H */ |