+static int mtd_check_oob_ops(struct mtd_info *mtd, loff_t offs,
+ struct mtd_oob_ops *ops)
+{
+ /*
+ * Some users are setting ->datbuf or ->oobbuf to NULL, but are leaving
+ * ->len or ->ooblen uninitialized. Force ->len and ->ooblen to 0 in
+ * this case.
+ */
+ if (!ops->datbuf)
+ ops->len = 0;
+
+ if (!ops->oobbuf)
+ ops->ooblen = 0;
+
+ if (offs < 0 || offs + ops->len > mtd->size)
+ return -EINVAL;
+
+ if (ops->ooblen) {
+ size_t maxooblen;
+
+ if (ops->ooboffs >= mtd_oobavail(mtd, ops))
+ return -EINVAL;
+
+ maxooblen = ((size_t)(mtd_div_by_ws(mtd->size, mtd) -
+ mtd_div_by_ws(offs, mtd)) *
+ mtd_oobavail(mtd, ops)) - ops->ooboffs;
+ if (ops->ooblen > maxooblen)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+