From: Victoria Milhoan Subject: [PATCH 07/12] crypto: caam - Use local sg pointers to walk the scatterlist Date: Wed, 29 Jul 2015 20:58:24 -0700 Message-ID: <1438228709-27650-8-git-send-email-vicki.milhoan@freescale.com> References: <1438228709-27650-1-git-send-email-vicki.milhoan@freescale.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , , , To: Return-path: Received: from mail-bl2on0122.outbound.protection.outlook.com ([65.55.169.122]:2656 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751074AbbG3EOG (ORCPT ); Thu, 30 Jul 2015 00:14:06 -0400 In-Reply-To: <1438228709-27650-1-git-send-email-vicki.milhoan@freescale.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: Avoid moving the head of the scatterlist entry by using temporary pointers to walk the scatterlist. Signed-off-by: Victoria Milhoan --- drivers/crypto/caam/sg_sw_sec4.h | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/drivers/crypto/caam/sg_sw_sec4.h b/drivers/crypto/caam/sg_sw_sec4.h index 711bb39..18cd6d1 100644 --- a/drivers/crypto/caam/sg_sw_sec4.h +++ b/drivers/crypto/caam/sg_sw_sec4.h @@ -105,9 +105,15 @@ static inline void dma_unmap_sg_chained( { if (unlikely(chained)) { int i; + struct scatterlist *tsg = sg; + + /* + * Use a local copy of the sg pointer to avoid moving the + * head of the list pointed to by sg as we walk the list. + */ for (i = 0; i < nents; i++) { - dma_unmap_sg(dev, sg, 1, dir); - sg = sg_next(sg); + dma_unmap_sg(dev, tsg, 1, dir); + tsg = sg_next(tsg); } } else if (nents) { dma_unmap_sg(dev, sg, nents, dir); @@ -118,19 +124,23 @@ static inline int dma_map_sg_chained( struct device *dev, struct scatterlist *sg, unsigned int nents, enum dma_data_direction dir, bool chained) { - struct scatterlist *first = sg; - if (unlikely(chained)) { int i; + struct scatterlist *tsg = sg; + + /* + * Use a local copy of the sg pointer to avoid moving the + * head of the list pointed to by sg as we walk the list. + */ for (i = 0; i < nents; i++) { - if (!dma_map_sg(dev, sg, 1, dir)) { - dma_unmap_sg_chained(dev, first, i, dir, + if (!dma_map_sg(dev, tsg, 1, dir)) { + dma_unmap_sg_chained(dev, sg, i, dir, chained); nents = 0; break; } - sg = sg_next(sg); + tsg = sg_next(tsg); } } else nents = dma_map_sg(dev, sg, nents, dir); -- 2.1.4