Zhihao Cheng a89d69a44e mtd: mtdconcat: Check _read, _write callbacks existence before assignment
Since 2431c4f5b4 ("mtd: Implement mtd_{read,write}() as wrappers
around mtd_{read,write}_oob()") don't allow _write|_read and
_write_oob|_read_oob existing at the same time, we should check the
existence of callbacks "_read and _write" from subdev's master device
(We can trust master device since it has been registered) before
assigning, otherwise following warning occurs while making
concatenated device:

  WARNING: CPU: 2 PID: 6728 at drivers/mtd/mtdcore.c:595
  add_mtd_device+0x7f/0x7b0

Fixes: 2431c4f5b4 ("mtd: Implement mtd_{read,write}() around ...")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210817114857.2784825-3-chengzhihao1@huawei.com
2021-08-17 18:43:33 +02:00
2021-07-11 15:07:40 -07:00

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