crypto: caam - Handle errors in dma_map_sg_chained

Currently dma_map_sg_chained does not handle errors from the
underlying dma_map_sg calls.  This patch adds rollback in case
of an error by simply calling dma_unmap_sg_chained for the ones
that we've already mapped.

All current callers ignore the return value so this should have
no impact on them.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 21 insertions, 14 deletions

diff --git a/drivers/crypto/caam/sg_sw_sec4.h b/drivers/crypto/caam/sg_sw_sec4.h
index efbc1db8da53..b68b74cc7b77 100644
--- a/drivers/crypto/caam/sg_sw_sec4.h
+++ b/drivers/crypto/caam/sg_sw_sec4.h
@@ -100,34 +100,41 @@ static inline int sg_count(struct scatterlist *sg_list, int nbytes,
         return sg_nents;
 }
 
-static int dma_map_sg_chained(struct device *dev, struct scatterlist *sg,
-                              unsigned int nents, enum dma_data_direction dir,
-                              bool chained)
+static inline void dma_unmap_sg_chained(
+        struct device *dev, struct scatterlist *sg, unsigned int nents,
+        enum dma_data_direction dir, bool chained)
 {
         if (unlikely(chained)) {
                 int i;
                 for (i = 0; i < nents; i++) {
-                        dma_map_sg(dev, sg, 1, dir);
+                        dma_unmap_sg(dev, sg, 1, dir);
                         sg = sg_next(sg);
                 }
-        } else {
-                dma_map_sg(dev, sg, nents, dir);
+        } else if (nents) {
+                dma_unmap_sg(dev, sg, nents, dir);
         }
-        return nents;
 }
 
-static int dma_unmap_sg_chained(struct device *dev, struct scatterlist *sg,
-                                unsigned int nents, enum dma_data_direction dir,
-                                bool chained)
+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;
                 for (i = 0; i < nents; i++) {
-                        dma_unmap_sg(dev, sg, 1, dir);
+                        if (!dma_map_sg(dev, sg, 1, dir)) {
+                                dma_unmap_sg_chained(dev, first, i, dir,
+                                                     chained);
+                                nents = 0;
+                                break;
+                        }
+
                         sg = sg_next(sg);
                 }
-        } else {
-                dma_unmap_sg(dev, sg, nents, dir);
-        }
+        } else
+                nents = dma_map_sg(dev, sg, nents, dir);
+
         return nents;
 }