From: Ulf Hansson <ulf.hansson@linaro.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: rjw@rjwysocki.net, lukasz.luba@arm.com, robh@kernel.org,
heiko@sntech.de, arnd@linaro.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org, "Rafael J. Wysocki" <rafael@kernel.org>,
Daniel Lezcano <daniel.lezcano@kernel.org>
Subject: Re: [PATCH v5 2/6] powercap/drivers/dtpm: Add hierarchy creation
Date: Fri, 7 Jan 2022 16:54:01 +0100 [thread overview]
Message-ID: <CAPDyKFqzxnfh0kow5mzoApFMQpKOAv=e1b7Cy9H-iEh99Wmagw@mail.gmail.com> (raw)
In-Reply-To: <8fcc0ef8-b0c7-da73-434f-31c88896aed5@linaro.org>
[...]
> >> +static int dtpm_for_each_child(const struct dtpm_node *hierarchy,
> >> + const struct dtpm_node *it, struct dtpm *parent)
> >> +{
> >> + struct dtpm *dtpm;
> >> + int i, ret;
> >> +
> >> + for (i = 0; hierarchy[i].name; i++) {
> >> +
> >> + if (hierarchy[i].parent != it)
> >> + continue;
> >> +
> >> + dtpm = dtpm_node_callback[hierarchy[i].type](&hierarchy[i], parent);
> >> + if (!dtpm || IS_ERR(dtpm))
> >> + continue;
> >> +
> >> + ret = dtpm_for_each_child(hierarchy, &hierarchy[i], dtpm);
> >
> > Why do you need to recursively call dtpm_for_each_child() here?
> >
> > Is there a restriction on how the dtpm core code manages adding
> > children/parents?
>
> [ ... ]
>
> The recursive call is needed given the structure of the tree in an array
> in order to connect with the parent.
Right, I believe I understand what you are trying to do here, but I am
not sure if this is the best approach to do this. Maybe it is.
The problem is that we are also allocating memory for a dtpm and we
call dtpm_register() on it in this execution path - and this memory
doesn't get freed up nor unregistered, if any of the later recursive
calls to dtpm_for_each_child() fails.
The point is, it looks like it can get rather messy with the recursive
calls to cope with the error path. Maybe it's easier to store the
allocated dtpms in a list somewhere and use this to also find a
reference of a parent?
Later on, when we may decide to implement "dtpm_destroy_hierarchy()"
(or whatever we would call such interface), you probably need a list
of the allocated dtpms anyway, don't you think?
[...]
Kind regards
Uffe
next prev parent reply other threads:[~2022-01-07 15:54 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-18 13:00 [PATCH v5 0/6] powercap/drivers/dtpm: Create the dtpm hierarchy Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 1/6] powercap/drivers/dtpm: Move dtpm table from init to data section Daniel Lezcano
2021-12-31 13:33 ` Ulf Hansson
2022-01-04 8:57 ` Daniel Lezcano
2022-01-07 13:15 ` Daniel Lezcano
2022-01-07 14:49 ` Ulf Hansson
2022-01-10 13:33 ` Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 2/6] powercap/drivers/dtpm: Add hierarchy creation Daniel Lezcano
2021-12-31 13:45 ` Ulf Hansson
2022-01-05 16:00 ` Daniel Lezcano
2022-01-07 15:54 ` Ulf Hansson [this message]
2022-01-10 15:55 ` Daniel Lezcano
2022-01-11 8:28 ` Ulf Hansson
2022-01-11 17:52 ` Daniel Lezcano
2022-01-12 12:00 ` Ulf Hansson
2022-01-14 19:15 ` Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 3/6] powercap/drivers/dtpm: Add CPU DT initialization support Daniel Lezcano
2021-12-31 13:46 ` Ulf Hansson
2021-12-18 13:00 ` [PATCH v5 4/6] powercap/drivers/dtpm: Add dtpm devfreq with energy model support Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 5/6] rockchip/soc/drivers: Add DTPM description for rk3399 Daniel Lezcano
2021-12-31 13:57 ` Ulf Hansson
2022-01-04 9:29 ` Geert Uytterhoeven
2022-01-05 9:21 ` Daniel Lezcano
2022-01-05 11:25 ` Daniel Lezcano
2021-12-18 13:00 ` [PATCH v5 6/6] qcom/soc/drivers: Add DTPM description for sdm845 Daniel Lezcano
2021-12-18 19:47 ` Steev Klimaszewski
2021-12-18 20:11 ` Daniel Lezcano
2021-12-19 18:44 ` Steev Klimaszewski
2021-12-19 20:27 ` Daniel Lezcano
2022-01-07 19:27 ` Bjorn Andersson
2022-01-07 22:07 ` Daniel Lezcano
2022-01-07 23:51 ` Bjorn Andersson
2021-12-23 13:20 ` [PATCH v5 0/6] powercap/drivers/dtpm: Create the dtpm hierarchy Daniel Lezcano
2021-12-23 13:32 ` Ulf Hansson
2021-12-23 13:42 ` Daniel Lezcano
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