linux-kernel - Re: [PATCH v5 1/5] firmware: document user mode helper lock usage

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Date:   Wed, 5 Oct 2016 22:41:26 +0200
From:   "Luis R. Rodriguez" <mcgrof@...nel.org>
To:     Ming Lei <ming.lei@...onical.com>
Cc:     "Luis R. Rodriguez" <mcgrof@...nel.org>,
        Daniel Wagner <wagi@...om.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "rafael.j.wysocki" <rafael.j.wysocki@...el.com>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Takashi Iwai <tiwai@...e.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Arend van Spriel <arend.vanspriel@...adcom.com>,
        Daniel Wagner <daniel.wagner@...-carit.de>
Subject: Re: [PATCH v5 1/5] firmware: document user mode helper lock usage

On Thu, Sep 22, 2016 at 10:36:39AM +0800, Ming Lei wrote:
> On Sat, Sep 10, 2016 at 6:14 AM, Luis R. Rodriguez <mcgrof@...nel.org> wrote:
> > On Fri, Sep 09, 2016 at 02:12:20PM +0200, Daniel Wagner wrote:
> >> From: Daniel Wagner <daniel.wagner@...-carit.de>
> >>
> >> The lock is also used to generate warnings when a direct
> >> firmware load is requested too early.
> >
> > I've determined the firmware cache lets us bail out of this
> > consideration now. If Ming agrees with the logic we don't need this
> > patch and you can continue as you had intended. Sorry for the trouble.
> 
> IMO it is helpful to add comment about using the lock for direct loading,
> and we can sort it out in future if anyone want to improve it.
> 
> So for this patch, I am fine.

Yeah that's fine too. Thew new API, the driver data API will not use the UMH
lock, so we can just skip the lock there if we feel mushy about removing
it from the existing API on direct firmware loading. From what I've determined
though its simply not needed.

  Luis