target/linux/generic/pending-4.14/491-ubi-auto-create-ubiblock-device-for-rootfs.patch

   1 From: Daniel Golle <daniel@makrotopia.org>
   2 Subject: ubi: auto-create ubiblock device for rootfs
   3
   4 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
   5 ---
   6  drivers/mtd/ubi/block.c | 42 ++++++++++++++++++++++++++++++++++++++++++
   7  1 file changed, 42 insertions(+)
   8
   9 --- a/drivers/mtd/ubi/block.c
  10 +++ b/drivers/mtd/ubi/block.c
  11 @@ -625,6 +625,44 @@ static void __init ubiblock_create_from_
  12         }
  13  }
  14
  15 +#define UBIFS_NODE_MAGIC  0x06101831
  16 +static inline int ubi_vol_is_ubifs(struct ubi_volume_desc *desc)
  17 +{
  18 +       int ret;
  19 +       uint32_t magic_of, magic;
  20 +       ret = ubi_read(desc, 0, (char *)&magic_of, 0, 4);
  21 +       if (ret)
  22 +               return 0;
  23 +       magic = le32_to_cpu(magic_of);
  24 +       return magic == UBIFS_NODE_MAGIC;
  25 +}
  26 +
  27 +static void __init ubiblock_create_auto_rootfs(void)
  28 +{
  29 +       int ubi_num, ret, is_ubifs;
  30 +       struct ubi_volume_desc *desc;
  31 +       struct ubi_volume_info vi;
  32 +
  33 +       for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++) {
  34 +               desc = ubi_open_volume_nm(ubi_num, "rootfs", UBI_READONLY);
  35 +               if (IS_ERR(desc))
  36 +                       continue;
  37 +
  38 +               ubi_get_volume_info(desc, &vi);
  39 +               is_ubifs = ubi_vol_is_ubifs(desc);
  40 +               ubi_close_volume(desc);
  41 +               if (is_ubifs)
  42 +                       break;
  43 +
  44 +               ret = ubiblock_create(&vi);
  45 +               if (ret)
  46 +                       pr_err("UBI error: block: can't add '%s' volume, err=%d\n",
  47 +                               vi.name, ret);
  48 +               /* always break if we get here */
  49 +               break;
  50 +       }
  51 +}
  52 +
  53  static void ubiblock_remove_all(void)
  54  {
  55         struct ubiblock *next;
  56 @@ -655,6 +693,10 @@ int __init ubiblock_init(void)
  57          */
  58         ubiblock_create_from_param();
  59
  60 +       /* auto-attach "rootfs" volume if existing and non-ubifs */
  61 +       if (IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV))
  62 +               ubiblock_create_auto_rootfs();
  63 +
  64         /*
  65          * Block devices are only created upon user requests, so we ignore
  66          * existing volumes.