mtd: do not use mtd->read_oob directly

Instead of checking whether 'mtd->read_oob' is defined, just call
'mtd_read_oob()' and handle the '-EOPNOTSUPP' error which will be returned
if the function is undefined.

Additionally, make 'mtd_write_oob()' return '-EOPNOTSUPP' if the function
is undefined.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index b72964049cdc..721a63ffeb96 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -320,6 +320,8 @@ static inline int mtd_read_oob(struct mtd_info *mtd, loff_t from,
                                struct mtd_oob_ops *ops)
 {
         ops->retlen = ops->oobretlen = 0;
+        if (!mtd->read_oob)
+                return -EOPNOTSUPP;
         return mtd->read_oob(mtd, from, ops);
 }
 
@@ -327,6 +329,8 @@ static inline int mtd_write_oob(struct mtd_info *mtd, loff_t to,
                                 struct mtd_oob_ops *ops)
 {
         ops->retlen = ops->oobretlen = 0;
+        if (!mtd->write_oob)
+                return -EOPNOTSUPP;
         return mtd->write_oob(mtd, to, ops);
 }