linux-kernel - Re: [PATCH] of: Add of_device_destroy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 09 May 2014 11:53:23 +0200
From:	Sylwester Nawrocki <s.nawrocki@...sung.com>
To:	Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Cc:	robh+dt@...nel.org, grant.likely@...aro.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] of: Add of_device_destroy_children() function

On 08/05/14 22:33, Jason Gunthorpe wrote:
> On Thu, May 08, 2014 at 06:37:49PM +0200, Sylwester Nawrocki wrote:
>> This patch adds a helper function to unregister devices which
>> were created by an of_platform_populate() call. The pattern
>> used here can already be found in multiple drivers. This helper
>> can now be used instead of repeating similar code in drivers.
> 
> I have a driver that does this as well, and what I found is that the
> remove must be in reverse order from the create or things explode, and
> that assumes the DT is topologically sorted according to dependency
> (so no deferred probe).
> 
> AFAIK, there is no analog to deferred probe for removal, and
> attempting to remove, say, a GPIO driver while an I2C bit bang is using
> it just fails.

Thanks for the feedback, I knew I could be missing some of nasty
details like this. Looks like we need a complete implementation
of of_platform_unpopulate(). Since the are cases where the remove
order is insignificant, I'm wondering whether it still would be
useful to have a helper like device_unregister_children() which
would remove only direct children of a device ? At least this
solves my current problem.

Since the dependencies will likely never be fully described in DT
I guess we would need to create a list while actually creating
devices, to be able to walk in reverse order while destroying them.

--
Regards,
Sylwester

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/