diff options
| author | Eric Biggers <ebiggers@google.com> | 2025-02-19 10:23:24 -0800 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2025-03-02 15:19:43 +0800 |
| commit | e21d01a2a3f56ee422cd155bf06c5e572523fcc1 (patch) | |
| tree | da488347e5634620fb212a40bfbb1fdb8e551f5b /crypto | |
| parent | 3bd4b2c603fce29f6d26da1579d5a013b70b9453 (diff) | |
crypto: scatterwalk - add new functions for skipping data
Add scatterwalk_skip() to skip the given number of bytes in a
scatter_walk. Previously support for skipping was provided through
scatterwalk_copychunks(..., 2) followed by scatterwalk_done(), which was
confusing and less efficient.
Also add scatterwalk_start_at_pos() which starts a scatter_walk at the
given position, equivalent to scatterwalk_start() + scatterwalk_skip().
This addresses another common need in a more streamlined way.
Later patches will convert various users to use these functions.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/scatterwalk.c | 15 |
1 files changed, 15 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; |