Re: [PATCH] clk: kirkwood: use kzalloc_flex

Brian Masney
2026-03-30T13:13:10Z

On Wed, Mar 25, 2026 at 09:55:55PM -0700, Rosen Penev wrote:
> Simplify allocation by using a flexible array member and kzalloc_flex to
> combine allocations.
>
> Add __counted_by for extra runtime analysis. Move counting variable
> assignment to right after allocation as required by __counted_by.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
> drivers/clk/mvebu/kirkwood.c | 19 ++++++++-----------
> 1 file changed, 8 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/clk/mvebu/kirkwood.c b/drivers/clk/mvebu/kirkwood.c
> index ed061d82fb65..fc2972538008 100644
> --- a/drivers/clk/mvebu/kirkwood.c
> +++ b/drivers/clk/mvebu/kirkwood.c
> @@ -253,8 +253,8 @@ struct clk_muxing_soc_desc {
>
> struct clk_muxing_ctrl {
> spinlock_t *lock;
> - struct clk **muxes;
> int num_muxes;
> + struct clk *muxes[] __counted_by(num_muxes);
> };
>
> static const char *powersave_parents[] = {
> @@ -297,21 +297,18 @@ static void __init kirkwood_clk_muxing_setup(struct device_node *np,
> if (WARN_ON(!base))
> return;
>
> - ctrl = kzalloc_obj(*ctrl);
> - if (WARN_ON(!ctrl))
> - goto ctrl_out;
> -
> - /* lock must already be initialized */
> - ctrl->lock = &ctrl_gating_lock;
> -
> /* Count, allocate, and register clock muxes */
> for (n = 0; desc[n].name;)
> n++;
>
> + ctrl = kzalloc_flex(*ctrl, muxes, n);
> + if (WARN_ON(!ctrl))
> + goto ctrl_out;
> +
> ctrl->num_muxes = n;
> - ctrl->muxes = kzalloc_objs(struct clk *, ctrl->num_muxes);
> - if (WARN_ON(!ctrl->muxes))
> - goto muxes_out;

Question from Sashiko:

https://sashiko.dev/#/patchset/20260326045555.240730-1-rosenp%40gmail.com

This isn't a bug, but since the goto muxes_out error path was removed here,
should the muxes_out label and its kfree(ctrl) be removed at the end of the
function?
They appear to be dead code now and might cause an unused label warning:
return;
muxes_out:
kfree(ctrl);
ctrl_out:
iounmap(base);
}

Brian

> +
> + /* lock must already be initialized */
> + ctrl->lock = &ctrl_gating_lock;
>
> for (n = 0; n < ctrl->num_muxes; n++) {
> ctrl->muxes[n] = clk_register_mux(NULL, desc[n].name,
> --
> 2.53.0
>