Re: [PATCH 1/6] clk: Remove recursion in clk_core_{prepare,enable}()

From: dbasehore .
Date: Wed Oct 24 2018 - 16:09:22 EST


On Wed, Oct 24, 2018 at 6:07 AM Stephen Boyd <sboyd@xxxxxxxxxx> wrote:
>
> Quoting Derek Basehore (2018-10-23 18:31:27)
> > From: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxx>
> > Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
> > Signed-off-by: Derek Basehore <dbasehore@xxxxxxxxxxxx>
>
> 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/