Re: [RFC] opp: Fixup release of clock when using set/put clkname

From: Viresh Kumar
Date: Tue Apr 14 2020 - 03:18:33 EST


On 14-04-20, 12:45, Rajendra Nayak wrote:
> Fixup dev_pm_opp_put_clkname() to check for a valid clock pointer
> before it does a clk_put, since its likely that
> _opp_table_kref_release() has already done a clk_put. Also fixup

kref release is the last thing that happens on the table, it can't get
called after dev_pm_opp_put_clkname().

> _opp_table_kref_release() to set the clock pointer to ERR_PTR(-EINVAL)
> after its done doing a clk_put so dev_pm_opp_put_clkname() can then
> catch it.
>
> Signed-off-by: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx>
> ---
> drivers/opp/core.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index e4f01e7..6d064a8 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -1061,8 +1061,10 @@ static void _opp_table_kref_release(struct kref *kref)
> _of_clear_opp_table(opp_table);
>
> /* Release clk */
> - if (!IS_ERR(opp_table->clk))
> + if (!IS_ERR(opp_table->clk)) {
> clk_put(opp_table->clk);
> + opp_table->clk = ERR_PTR(-EINVAL);
> + }
>
> WARN_ON(!list_empty(&opp_table->opp_list));
>
> @@ -1744,8 +1746,10 @@ void dev_pm_opp_put_clkname(struct opp_table *opp_table)
> /* Make sure there are no concurrent readers while updating opp_table */
> WARN_ON(!list_empty(&opp_table->opp_list));
>
> - clk_put(opp_table->clk);
> - opp_table->clk = ERR_PTR(-EINVAL);
> + if (!IS_ERR(opp_table->clk)) {
> + clk_put(opp_table->clk);
> + opp_table->clk = ERR_PTR(-EINVAL);
> + }
>
> dev_pm_opp_put_opp_table(opp_table);
> }
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation

--
viresh