linux-kernel - Re: [RFC PATCH 08/13] driver core: firmware loader: fix device lifetime

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Message-ID: <CACVXFVMxUKezcR5BBv6jM0wZr8UivF7dJGe1gLNiFx=1h4U59g@mail.gmail.com>
Date:	Thu, 26 Jul 2012 23:44:48 +0800
From:	Ming Lei <ming.lei@...onical.com>
To:	Borislav Petkov <bp@...64.org>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 08/13] driver core: firmware loader: fix device lifetime

On Thu, Jul 26, 2012 at 8:20 PM, Borislav Petkov <bp@...64.org> wrote:
>
> Ok, here's what I got from looking at the patch:
>
> Your commit message says: "Also request_firmware_nowait should be called
> in atomic context now, so fix the obsolete comments."
>
> Atomic context in my book means you're not allowed to sleep at all.

In fact, I mean the function can be called in atomic context now, and
I know some time ago the function will create kthread to execute
the request_firmware, and atomic context is not allowed.

So I remove the obsolete comment.

>
> But the comment says that it is possible to sleep a little. This is very
> wrongly formulated AFAICT.

The function can be run in both contexts, and I don't see any words which
says the function will sleep.

>
> But, since request_firmware_nowait receives a GFP mask as one of its
> arguments and some of its callers don't supply GFP_ATOMIC then this
> has nothing to do with atomic contexts at all. Then, you should simply
> explain in the comment why exactly callers aren't allowed to be sleeping
> for a long time. And using adjectives like "long" or "short" is very
> misleading in such explanations so please be more specific as to why the

It is the original one, and I don't think it is wrong. Also it
shouldn't be covered
by this patch.

Maybe I shouldn't have fixed the comment in this patch.


Thanks,
--
Ming Lei
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