crypto: caam - Use local sg pointers to walk the scatterlist

Avoid moving the head of the scatterlist entry by using temporary
pointers to walk the scatterlist.

Signed-off-by: Victoria Milhoan <vicki.milhoan@freescale.com>
Tested-by: Horia Geantă <horia.geanta@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 17 insertions, 7 deletions

diff --git a/drivers/crypto/caam/sg_sw_sec4.h b/drivers/crypto/caam/sg_sw_sec4.h
index 711bb3949779..18cd6d1f5870 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);