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From:   "dbasehore ." <dbasehore@chromium.org>
Date:   Wed, 24 Oct 2018 13:09:07 -0700
Message-ID: <CAGAzgspGA0CExLBrJvM8E7a1ybp=PRDz6kJ-dKyp0hi9db-19g@mail.gmail.com>
Subject: Re: [PATCH 1/6] clk: Remove recursion in clk_core_{prepare,enable}()
To:     sboyd@kernel.org
Cc:     linux-kernel <linux-kernel@vger.kernel.org>,
        linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org, linux-doc@vger.kernel.org,
        Michael Turquette <mturquette@baylibre.com>,
        =?UTF-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>,
        aisheng.dong@nxp.com, mchehab+samsung@kernel.org, corbet@lwn.net,
        Stephen Boyd <sboyd@codeaurora.org>, jbrunet@baylibre.com
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On Wed, Oct 24, 2018 at 6:07 AM Stephen Boyd <sboyd@kernel.org> wrote:
>
> Quoting Derek Basehore (2018-10-23 18:31:27)
> > From: Stephen Boyd <sboyd@codeaurora.org>
> >
> > Enabling and preparing clocks can be written quite naturally with
> > recursion. We start at some point in the tree and recurse up the
> > tree to find the oldest parent clk that needs to be enabled or
> > prepared. Then we enable/prepare and return to the caller, going
> > back to the clk we started at and enabling/preparing along the
> > way.
> >
> > The problem is recursion isn't great for kernel code where we
> > have a limited stack size. Furthermore, we may be calling this
> > code inside clk_set_rate() which also has recursion in it, so
> > we're really not looking good if we encounter a tall clk tree.
> >
> > Let's create a stack instead by looping over the parent chain and
> > collecting clks of interest. Then the enable/prepare becomes as
> > simple as iterating over that list and calling enable.
> >
> > Cc: Jerome Brunet <jbrunet@baylibre.com>
> > Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> > Signed-off-by: Derek Basehore <dbasehore@chromium.org>
>
> Did you change anything substantially? Or is it just a resend of my
> patch from a while ago? If you can add a link to the original and also
> describe what changed in a maintainer tag it would be much easier for me
> to compare.
>

It should just be your patch with the compilation warning fixed.

This is picked up from https://lore.kernel.org/patchwork/patch/814369/