linux-kernel - Re: [PATCH v1 2/4] firmware loader: simplify holding module for request

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Date:	Tue, 7 Jan 2014 22:53:57 +0800
From:	Ming Lei <ming.lei@...onical.com>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 2/4] firmware loader: simplify holding module for request_firmware

Hi Dmitry,

On Tue, Jan 7, 2014 at 3:56 PM, Dmitry Torokhov
<dmitry.torokhov@...il.com> wrote:
> Hi Ming,
>
> On Thu, Jun 06, 2013 at 08:01:48PM +0800, Ming Lei wrote:
>> module reference doesn't cover direct loading path, so this patch
>> simply holds the module in the whole life time of request_firmware()
>> to fix the problem.
>
> This does not make sense to me. If request_firmware() is executing that
> means some other module references it and module refcount already
> reflects that.

Yes, you are right, holding this module references in both
request_firmware() and request_firmware_direct() shouldn't
be necessary.

>
> We needed to pin module before Tejun's work ensuring that currently open
> sysfs entries won't keep related kobjects pinned after kernel marked
> them inactive. We can probably delete __module_get()/module_put() from
> firmware_class.c now.

But holding the reference for request_firmware_nowait() is needed.


Thanks,
--
Ming Lei
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