This patch adds the function scatterwalk_sg_copychunks which writes
a chunk of data from a scatterwalk to another scatterwalk.
It will be used by caam driver to remove the leading zeros
for the output data of the RSA algorithm, after the computation completes.
Signed-off-by: Tudor Ambarus <tudor-dan.ambarus@xxxxxxx>
---
crypto/scatterwalk.c | 26 ++++++++++++++++++++++++++
include/crypto/scatterwalk.h | 2 ++
2 files changed, 28 insertions(+)
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index ea5815c..bc3222d 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -125,6 +125,32 @@ void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
}
EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
+void scatterwalk_sg_copychunks(struct scatter_walk *dest,
+ struct scatter_walk *src, size_t nbytes)
+{
+ for (;;) {
+ unsigned int len_this_page = scatterwalk_pagelen(dest);
+ u8 *vaddr;
+
+ if (len_this_page > nbytes)
+ len_this_page = nbytes;
+
+ vaddr = scatterwalk_map(dest);
+ scatterwalk_copychunks(vaddr, src, len_this_page, 0);
+ scatterwalk_unmap(vaddr);
+
+ scatterwalk_advance(dest, len_this_page);
+
+ if (nbytes == len_this_page)
+ break;
+
+ nbytes -= len_this_page;
+
+ scatterwalk_pagedone(dest, 0, 1);
+ }
+}
+EXPORT_SYMBOL_GPL(scatterwalk_sg_copychunks);
+
int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes)
{
int offset = 0, n = 0;
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
index 35f99b6..8b799c5 100644
--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h
@@ -86,6 +86,8 @@ static inline void scatterwalk_unmap(void *vaddr)
void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
size_t nbytes, int out);
+void scatterwalk_sg_copychunks(struct scatter_walk *dest,
+ struct scatter_walk *src, size_t nbytes);
void *scatterwalk_map(struct scatter_walk *walk);
void scatterwalk_done(struct scatter_walk *walk, int out, int more);
--
1.8.3.1
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