Re: [PATCH] soc: qcom: rpmh: Dirt can only make you dirtier, not cleaner

From: Matthias Kaehlcke
Date: Sat Apr 18 2020 - 12:16:25 EST


On Fri, Apr 17, 2020 at 02:15:47PM -0700, Douglas Anderson wrote:
> Adding an item into the cache should never be able to make the cache
> cleaner. Use "|=" rather than "=" to update the dirty flag.
>
> Fixes: bb7000677a1b ("soc: qcom: rpmh: Update dirty flag only when data changes")
> Reported-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
>
> drivers/soc/qcom/rpmh.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
> index 3abbb08cd6e1..d1626a1328d7 100644
> --- a/drivers/soc/qcom/rpmh.c
> +++ b/drivers/soc/qcom/rpmh.c
> @@ -151,10 +151,10 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
> break;
> }
>
> - ctrlr->dirty = (req->sleep_val != old_sleep_val ||
> - req->wake_val != old_wake_val) &&
> - req->sleep_val != UINT_MAX &&
> - req->wake_val != UINT_MAX;
> + ctrlr->dirty |= (req->sleep_val != old_sleep_val ||
> + req->wake_val != old_wake_val) &&
> + req->sleep_val != UINT_MAX &&
> + req->wake_val != UINT_MAX;
>
> unlock:
> spin_unlock_irqrestore(&ctrlr->cache_lock, flags);

Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>