mtd: return error code from mtd_unpoint

The 'mtd_unpoint()' API function should be able to return an error code because
it may fail if you specify incorrect offset. This patch changes this MTD API
function and amends all the drivers correspondingly.

Also return '-EOPNOTSUPP' from 'mtd_unpoint()' when the '->unpoint()' method is
undefined. We do not really need this currently, but this just makes
sense to be consistent with 'mtd_point()'.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index e2e545616b2a..8c243117c087 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -177,7 +177,7 @@ struct mtd_info {
         int (*_erase) (struct mtd_info *mtd, struct erase_info *instr);
         int (*_point) (struct mtd_info *mtd, loff_t from, size_t len,
                        size_t *retlen, void **virt, resource_size_t *phys);
-        void (*_unpoint) (struct mtd_info *mtd, loff_t from, size_t len);
+        int (*_unpoint) (struct mtd_info *mtd, loff_t from, size_t len);
         unsigned long (*_get_unmapped_area) (struct mtd_info *mtd,
                                              unsigned long len,
                                              unsigned long offset,
@@ -265,8 +265,10 @@ static inline int mtd_point(struct mtd_info *mtd, loff_t from, size_t len,
 }
 
 /* We probably shouldn't allow XIP if the unpoint isn't a NULL */
-static inline void mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
+static inline int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
 {
+        if (!mtd->_point)
+                return -EOPNOTSUPP;
         return mtd->_unpoint(mtd, from, len);
 }