From: Johan Hovold <johan@kernel.org>
To: Niklas Cassel <niklas.cassel@linaro.org>
Cc: Johan Hovold <johan@kernel.org>,
broonie@kernel.org, Liam Girdwood <lgirdwood@gmail.com>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] regulator: qcom_spmi: Fix warning Bad of_node_put()
Date: Mon, 16 Jul 2018 16:23:10 +0200 [thread overview]
Message-ID: <20180716142310.GQ10204@localhost> (raw)
In-Reply-To: <20180716132931.GA866@centauri.lan>
On Mon, Jul 16, 2018 at 03:29:31PM +0200, Niklas Cassel wrote:
> On Mon, Jul 16, 2018 at 02:01:34PM +0200, Johan Hovold wrote:
> > Hi Niklas,
> >
> > On Mon, Jul 16, 2018 at 01:35:22PM +0200, Niklas Cassel wrote:
> > > For of_find_node_by_name(), you typically pass what the previous call
> > > returned. Therefore, of_find_node_by_name() increases the refcount of
> > > the returned node, and decreases the refcount of the node passed as the
> > > first argument.
> > >
> > > However, in this case we don't pass what the previous call returned,
> > > so we have to increase the refcount of the first argument to compensate.
> >
> > I don't think this is the right fix. of_find_node_by_name() should
> > generally not be used by drivers in the first place as it searches the
> > entire tree and can end up matching an entirely unrelated node.
> >
> > I haven't looked at the device-tree binding in question, but you
> > probably want to use something like of_get_child_by_name() instead.
> >
>
> Hello Johan,
>
> of_find_node_by_name() will only search the whole tree if the
> first argument is NULL, which isn't the case here.
It's searching the entire tree *starting* at its first argument, which
means you may end up matching a completely unrelated node (i.e. not a
child or even descendant) elsewhere in the tree.
> However, of_get_child_by_name() is indeed better suited here.
> Will send out a v2.
Unless you are doing a tree-wide search, using of_get_child_by_name() is
simply wrong.
I fixed up most of these bugs a few releases ago, but they keep on
creeping in.
> Thank you for your feedback, it is much appreciated :)
No worries.
Johan
next prev parent reply other threads:[~2018-07-16 14:23 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-16 11:35 [PATCH 0/4] regulator: qcom_spmi: fix Bad of_node_put() splat Niklas Cassel
2018-07-16 11:35 ` [PATCH 1/4] regulator: qcom_spmi: Fix warning Bad of_node_put() Niklas Cassel
2018-07-16 12:01 ` Johan Hovold
2018-07-16 13:29 ` Niklas Cassel
2018-07-16 14:23 ` Johan Hovold [this message]
2018-07-16 11:35 ` [PATCH 2/4] regulator: qcom_spmi: Use correct regmap when checking for error Niklas Cassel
2018-07-20 16:45 ` Applied "regulator: qcom_spmi: Use correct regmap when checking for error" to the regulator tree Mark Brown
2018-07-16 11:35 ` [PATCH 3/4] regulator: qcom_spmi: Do not initialise static to NULL Niklas Cassel
2018-07-20 16:45 ` Applied "regulator: qcom_spmi: Do not initialise static to NULL" to the regulator tree Mark Brown
2018-07-16 11:35 ` [PATCH 4/4] regulator: qcom_spmi: Indent with tabs instead of spaces Niklas Cassel
2018-07-20 16:45 ` Applied "regulator: qcom_spmi: Indent with tabs instead of spaces" to the regulator tree Mark Brown
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