From 923a6e5e5f171317ac8bb462ac4b814fa7880d3c Mon Sep 17 00:00:00 2001
From: Tadeusz Struk <tadeusz.struk@intel.com>
Date: Mon, 13 Oct 2014 18:24:26 -0700
Subject: [PATCH] crypto: qat - Prevent dma mapping zero length assoc data

Do not attempt to dma map associated data if it is zero length.

Cc: stable@vger.kernel.org
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Tested-by: Nikolay Aleksandrov <nikolay@redhat.com>
Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 drivers/crypto/qat/qat_common/qat_algs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/crypto/qat/qat_common/qat_algs.c b/drivers/crypto/qat/qat_common/qat_algs.c
index f2e2f158cfbe..699ccf44e9bb 100644
--- a/drivers/crypto/qat/qat_common/qat_algs.c
+++ b/drivers/crypto/qat/qat_common/qat_algs.c
@@ -605,6 +605,8 @@ static int qat_alg_sgl_to_bufl(struct qat_crypto_instance *inst,
 		goto err;
 
 	for_each_sg(assoc, sg, assoc_n, i) {
+		if (!sg->length)
+			continue;
 		bufl->bufers[bufs].addr = dma_map_single(dev,
 							 sg_virt(sg),
 							 sg->length,