linux-kernel - Re: [PATCH 6/9] drm/msm/dsi_phy_28nm_8960: Use stack memory for temporary clock names

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Message-ID: <CAA8EJpqhqtc1A0SJqAhOveZcdsBEjPNZLpR3tTM2L3+p3QtiWA@mail.gmail.com>
Date:   Tue, 24 May 2022 01:45:29 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Marijn Suijten <marijn.suijten@...ainline.org>
Cc:     phone-devel@...r.kernel.org, Stephen Boyd <sboyd@...nel.org>,
        ~postmarketos/upstreaming@...ts.sr.ht,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Martin Botka <martin.botka@...ainline.org>,
        Jami Kettunen <jami.kettunen@...ainline.org>,
        Michael Turquette <mturquette@...libre.com>,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rajeev Nandan <quic_rajeevny@...cinc.com>,
        Vladimir Lypak <vladimir.lypak@...il.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Marek <jonathan@...ek.ca>, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org
Subject: Re: [PATCH 6/9] drm/msm/dsi_phy_28nm_8960: Use stack memory for
 temporary clock names

On Tue, 24 May 2022 at 00:38, Marijn Suijten
<marijn.suijten@...ainline.org> wrote:
>
> The clock names formatted into the hw_clk's init structure are only used
> for the duration of the registration function where they are kstrdup'ed,
> making it unnecessary to keep the allocations alive for the duration of
> the device (through devm).
>
> Just like the other DSI PHY PLL clock trees, use a stack-local char
> array and save on memory outside of the pll_28nm_register function.
>
> Signed-off-by: Marijn Suijten <marijn.suijten@...ainline.org>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

Nit: we can use clk_name instead of vco_name too.

> ---
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c | 10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c
> index 943a7e847c90..554978fc434d 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c
> @@ -383,7 +383,7 @@ static int dsi_28nm_pll_restore_state(struct msm_dsi_phy *phy)
>
>  static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm, struct clk_hw **provided_clocks)
>  {
> -       char *clk_name, *vco_name;
> +       char clk_name[32], vco_name[32];
>         struct clk_init_data vco_init = {
>                 .parent_data = &(const struct clk_parent_data) {
>                         .fw_name = "ref",
> @@ -404,14 +404,6 @@ static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm, struct clk_hw **prov
>         if (!bytediv)
>                 return -ENOMEM;
>
> -       vco_name = devm_kzalloc(dev, 32, GFP_KERNEL);
> -       if (!vco_name)
> -               return -ENOMEM;
> -
> -       clk_name = devm_kzalloc(dev, 32, GFP_KERNEL);
> -       if (!clk_name)
> -               return -ENOMEM;
> -
>         snprintf(vco_name, 32, "dsi%dvco_clk", pll_28nm->phy->id);
>         vco_init.name = vco_name;
>
> --
> 2.36.1
>


-- 
With best wishes
Dmitry