diff options
| -rw-r--r-- | crypto/scatterwalk.c | 15 | ||||
| -rw-r--r-- | include/crypto/scatterwalk.h | 18 |
2 files changed, 33 insertions, 0 deletions
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c index 16f6ba896fb6..af436ad02e3f 100644 --- a/crypto/scatterwalk.c +++ b/crypto/scatterwalk.c @@ -15,6 +15,21 @@ #include <linux/module.h> #include <linux/scatterlist.h> +void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes) +{ + struct scatterlist *sg = walk->sg; + + nbytes += walk->offset - sg->offset; + + while (nbytes > sg->length) { + nbytes -= sg->length; + sg = sg_next(sg); + } + walk->sg = sg; + walk->offset = sg->offset + nbytes; +} +EXPORT_SYMBOL_GPL(scatterwalk_skip); + static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) { void *src = out ? buf : sgdata; diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h index 924efbaefe67..5c7765f601e0 100644 --- a/include/crypto/scatterwalk.h +++ b/include/crypto/scatterwalk.h @@ -33,6 +33,22 @@ static inline void scatterwalk_start(struct scatter_walk *walk, walk->offset = sg->offset; } +/* + * This is equivalent to scatterwalk_start(walk, sg) followed by + * scatterwalk_skip(walk, pos). + */ +static inline void scatterwalk_start_at_pos(struct scatter_walk *walk, + struct scatterlist *sg, + unsigned int pos) +{ + while (pos > sg->length) { + pos -= sg->length; + sg = sg_next(sg); + } + walk->sg = sg; + walk->offset = sg->offset + pos; +} + static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk) { unsigned int len = walk->sg->offset + walk->sg->length - walk->offset; @@ -92,6 +108,8 @@ static inline void scatterwalk_done(struct scatter_walk *walk, int out, scatterwalk_pagedone(walk, out, more); } +void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes); + void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out); |