lib: scatterlist: Fix to support no mapped sg

In function sg_split, the second sg_calculate_split will return -EINVAL when in_mapped_nents is 0. Indeed there is no need to do second sg_calculate_split and sg_split_mapped when in_mapped_nents is 0, as in_mapped_nents indicates no mapped entry in original sgl. Signed-off-by: Zhou Wang <[email protected]> Acked-by: Robert Jarzmik <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
kdave · Aug 8, 2019 · 79e178f · 79e178f
1 parent ba6f7da
commit 79e178f
Showing 1 changed file with 7 additions and 5 deletions.
diff --git a/lib/sg_split.c b/lib/sg_split.c
@@ -176,11 +176,13 @@ int sg_split(struct scatterlist *in, const int in_mapped_nents,
 	 * The order of these 3 calls is important and should be kept.
 	 */
 	sg_split_phys(splitters, nb_splits);
-	ret = sg_calculate_split(in, in_mapped_nents, nb_splits, skip,
-				 split_sizes, splitters, true);
-	if (ret < 0)
-		goto err;
-	sg_split_mapped(splitters, nb_splits);
+	if (in_mapped_nents) {
+		ret = sg_calculate_split(in, in_mapped_nents, nb_splits, skip,
+					 split_sizes, splitters, true);
+		if (ret < 0)
+			goto err;
+		sg_split_mapped(splitters, nb_splits);
+	}
 
 	for (i = 0; i < nb_splits; i++) {
 		out[i] = splitters[i].out_sg;