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>

diff --git a/drivers/crypto/caam/sg_sw_sec4.h b/drivers/crypto/caam/sg_sw_sec4.h
index 711bb39497796bef3189be6929331cce43451edf..18cd6d1f587049a63af53d28225cbbe1fb5a866d 100644 (file)
--- 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);