mtd: Make sure mtd->erasesize is valid even if the partition is of size 0

Commit 33f45c44d68b ("mtd: Do not allow MTD devices with inconsistent
erase properties") introduced a check to make sure ->erasesize and
->_erase values are consistent with the MTD_NO_ERASE flag.
This patch did not take the 0 bytes partition case into account which
can happen when the defined partition is outside the flash device memory
range. Fix that by setting the partition erasesize to the parent
erasesize.

Fixes: 33f45c44d68b ("mtd: Do not allow MTD devices with inconsistent erase properties")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: <stable@vger.kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Boris Brezillon <bbrezillon@kernel.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index e6d9467f6be032fc1412d063fc2c224a42b00852..37f174ccbcec4b1f10d0af717707a38fa46d4499 100644 (file)
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -480,6 +480,10 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent,
                /* let's register it anyway to preserve ordering */
                slave->offset = 0;
                slave->mtd.size = 0;
+
+               /* Initialize ->erasesize to make add_mtd_device() happy. */
+               slave->mtd.erasesize = parent->erasesize;
+
                printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
                        part->name);
                goto out_register;