Re: [PATCH 15/16] mtd: mtdcore: fix initcall level

From: Alexander Holler
Date: Tue Sep 08 2015 - 15:36:21 EST


Am 04.09.2015 um 06:00 schrieb Alexander Holler:
Am 02.09.2015 um 07:34 schrieb Alexander Holler:
Am 01.09.2015 um 23:19 schrieb Brian Norris:
Hi Alexander,

No judgment here for the rest of this series, but for this patch:

On Wed, Aug 26, 2015 at 02:28:27PM +0200, Alexander Holler wrote:
The mtd-core has to be initialized before other dependent mtd-drivers,
otherwise a crash might occur.

Currently mtd_init() is called in the initcall-level device, which is
the
same level where most mtd-drivers will end up. By luck this seemed to
have
been called most of the time before other mtd-drivers without having
been
explicitly enforced.

I can't really speak for the original authors, but it does not appear to
be entirely "by luck." Link order was one of the de facto ways to get
this ordering (though it's not really a great one), and mtdcore was
always linked first within the drivers/mtd/ directory structure.

But that's just background, I think this is worth fixing anyway. It
could, for instance, become a problem if drivers are located outside
drivers/mtd/; I see random board files in arch/ that register with MTD,
and I'm actually not sure how they have never tripped on this.

As I've just had a look at my patches in order to clean up the patch for parallel initialization (to post it here too):

drivers/mtd/ofparts.c has the same problem. In order to let the NAND-driver see the partitions defined in the DT I had to move this into another initcall level (fs sync) too.

Regards,

Alexander Holler
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