target/linux/generic/backport-4.19/048-v4.21-mtd-improve-calculating-partition-boundaries-when-ch.patch

   1 From 6750f61a13a0197c40e4a40739117493b15f19e8 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   3 Date: Tue, 20 Nov 2018 10:24:09 +0100
   4 Subject: [PATCH] mtd: improve calculating partition boundaries when checking
   5  for alignment
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 When checking for alignment mtd should check absolute offsets. It's
  11 important for subpartitions as it doesn't make sense to check their
  12 relative addresses.
  13
  14 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  15 Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
  16 ---
  17  drivers/mtd/mtdpart.c | 13 +++++++++++--
  18  1 file changed, 11 insertions(+), 2 deletions(-)
  19
  20 --- a/drivers/mtd/mtdpart.c
  21 +++ b/drivers/mtd/mtdpart.c
  22 @@ -61,6 +61,15 @@ static inline struct mtd_part *mtd_to_pa
  23         return container_of(mtd, struct mtd_part, mtd);
  24  }
  25
  26 +static u64 part_absolute_offset(struct mtd_info *mtd)
  27 +{
  28 +       struct mtd_part *part = mtd_to_part(mtd);
  29 +
  30 +       if (!mtd_is_partition(mtd))
  31 +               return 0;
  32 +
  33 +       return part_absolute_offset(part->parent) + part->offset;
  34 +}
  35
  36  /*
  37   * MTD methods which simply translate the effective address and pass through
  38 @@ -562,7 +571,7 @@ static struct mtd_part *allocate_partiti
  39         if (!(slave->mtd.flags & MTD_NO_ERASE))
  40                 wr_alignment = slave->mtd.erasesize;
  41
  42 -       tmp = slave->offset;
  43 +       tmp = part_absolute_offset(parent) + slave->offset;
  44         remainder = do_div(tmp, wr_alignment);
  45         if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
  46                 /* Doesn't start on a boundary of major erase size */
  47 @@ -573,7 +582,7 @@ static struct mtd_part *allocate_partiti
  48                         part->name);
  49         }
  50
  51 -       tmp = slave->mtd.size;
  52 +       tmp = part_absolute_offset(parent) + slave->mtd.size;
  53         remainder = do_div(tmp, wr_alignment);
  54         if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
  55                 slave->mtd.flags &= ~MTD_WRITEABLE;