NOMMU: Present backing device capabilities for MTD chardevs

Present backing device capabilities for MTD character device files to allow
NOMMU mmap to do direct mapping where possible.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Bernd Schmidt <bernd.schmidt@analog.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 144e6b613a77..06d5b9d8853a 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -84,6 +84,18 @@ static void part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
         part->master->unpoint(part->master, from + part->offset, len);
 }
 
+static unsigned long part_get_unmapped_area(struct mtd_info *mtd,
+                                            unsigned long len,
+                                            unsigned long offset,
+                                            unsigned long flags)
+{
+        struct mtd_part *part = PART(mtd);
+
+        offset += part->offset;
+        return part->master->get_unmapped_area(part->master, len, offset,
+                                               flags);
+}
+
 static int part_read_oob(struct mtd_info *mtd, loff_t from,
                 struct mtd_oob_ops *ops)
 {
@@ -342,6 +354,7 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
 
         slave->mtd.name = part->name;
         slave->mtd.owner = master->owner;
+        slave->mtd.backing_dev_info = master->backing_dev_info;
 
         slave->mtd.read = part_read;
         slave->mtd.write = part_write;
@@ -354,6 +367,8 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
                 slave->mtd.unpoint = part_unpoint;
         }
 
+        if (master->get_unmapped_area)
+                slave->mtd.get_unmapped_area = part_get_unmapped_area;
         if (master->read_oob)
                 slave->mtd.read_oob = part_read_oob;
         if (master->write_oob)