Commit 257aff51 authored by Joel Fernandes's avatar Joel Fernandes Committed by Herbert Xu
Browse files

crypto: scatterwalk - Add support for calculating number of SG elements 



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: default avatarJoel Fernandes <joelf@ti.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent b4eba0ca

crypto/scatterwalk.c

+22 −0
Original line number Diff line number Diff line
@@ -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);

include/crypto/scatterwalk.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */

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