Crypto layer only passes nbytes to encrypt but in omap-aes driver we
need to know number of SG elements to pass to dmaengine slave API.
We add function for the same to scatterwalk library.
Signed-off-by: Joel Fernandes <joelf@xxxxxx>
---
crypto/scatterwalk.c | 22 ++++++++++++++++++++++
include/crypto/scatterwalk.h | 2 ++
2 files changed, 24 insertions(+)
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 7281b8a..79ca227 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 3744d2a..13621cc 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 */
--
1.7.9.5
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