crypto: omap-aes - Populate number of SG elements

Crypto layer only passes nbytes but number of SG elements is needed for mapping
or unmapping SGs at one time using dma_map* API and also needed to pass in for
dmaengine prep function.

We call function added to scatterwalk for this purpose in omap_aes_handle_queue
to populate the values which are used later.
Signed-off-by: NJoel Fernandes <joelf@ti.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/omap-aes.c

@@ -165,6 +165,8 @@ struct omap_aes_dev {
 	void			*buf_out;
 	int			dma_out;
 	struct dma_chan		*dma_lch_out;
+	int			in_sg_len;
+	int			out_sg_len;
 	dma_addr_t		dma_addr_out;
 
 	const struct omap_aes_pdata	*pdata;
@@ -725,6 +727,10 @@ static int omap_aes_handle_queue(struct omap_aes_dev *dd,
 	dd->out_offset = 0;
 	dd->out_sg = req->dst;
 
+	dd->in_sg_len = scatterwalk_bytes_sglen(dd->in_sg, dd->total);
+	dd->out_sg_len = scatterwalk_bytes_sglen(dd->out_sg, dd->total);
+	BUG_ON(dd->in_sg_len < 0 || dd->out_sg_len < 0);
+
 	rctx = ablkcipher_request_ctx(req);
 	ctx = crypto_ablkcipher_ctx(crypto_ablkcipher_reqtfm(req));
 	rctx->mode &= FLAGS_MODE_MASK;