Commit 1eeef2d7483a ("mtd: handle partitioning on devices with 0 erasesize") introduced a regression on heterogeneous erase region devices. Alignment of the partition was tested against the master eraseblock size which can be bigger than the slave one, thus leading to some partitions being marked as read-only. Update wr_alignment to match this slave erasesize after this erasesize has been determined by picking the biggest erasesize of all the regions embedded in the MTD partition. Reported-by: Mathias Thore <Mathias.Thore@xxxxxxxxxxxx> Fixes: 1eeef2d7483a ("mtd: handle partitioning on devices with 0 erasesize") Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> --- Changes in v2: - Fix build error reported by Mathias --- drivers/mtd/mtdpart.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index 5736b0c90b33..a308e707392d 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -581,6 +581,14 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent, slave->mtd.erasesize = parent->erasesize; } + /* + * Slave erasesize might differ from the master one if the master + * exposes several regions with different erasesize. Adjust + * wr_alignment accordingly. + */ + if (!(slave->mtd.flags & MTD_NO_ERASE)) + wr_alignment = slave->mtd.erasesize; + tmp = slave->offset; remainder = do_div(tmp, wr_alignment); if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) { -- 2.11.0