diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 63bbefdffc81..cf8deecc39ef 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -638,8 +638,8 @@ static ssize_t writeback_store(struct device *dev,
 		if (strncmp(buf, PAGE_WB_SIG, sizeof(PAGE_WB_SIG) - 1))
 			return -EINVAL;
 
-		ret = kstrtol(buf + sizeof(PAGE_WB_SIG) - 1, 10, &index);
-		if (ret || index >= nr_pages)
+		if (kstrtol(buf + sizeof(PAGE_WB_SIG) - 1, 10, &index) ||
+				index >= nr_pages)
 			return -EINVAL;
 
 		nr_pages = 1;
@@ -663,7 +663,7 @@ static ssize_t writeback_store(struct device *dev,
 		goto release_init_lock;
 	}
 
-	while (nr_pages--) {
+	for (; nr_pages != 0; index++, nr_pages--) {
 		struct bio_vec bvec;
 
 		bvec.bv_page = page;