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Message-ID: <581fb060128519d29c06f797ee8ec7c8d0e60ca0.camel@gmail.com>
Subject: Re: [PATCH v2 2/2] of: overlay: Synchronize of_overlay_remove()
 with the devlink removals
From: Nuno =?ISO-8859-1?Q?S=E1?= <noname.nuno@gmail.com>
To: Herve Codina <herve.codina@bootlin.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, "Rafael J. Wysocki"
 <rafael@kernel.org>, Rob Herring <robh+dt@kernel.org>, Frank Rowand
 <frowand.list@gmail.com>, Lizhi Hou <lizhi.hou@amd.com>, Max Zhen
 <max.zhen@amd.com>, Sonal Santan <sonal.santan@amd.com>, Stefano Stabellini
 <stefano.stabellini@xilinx.com>, Jonathan Cameron
 <Jonathan.Cameron@Huawei.com>,  linux-kernel@vger.kernel.org,
 devicetree@vger.kernel.org, Allan Nielsen <allan.nielsen@microchip.com>,
 Horatiu Vultur <horatiu.vultur@microchip.com>,  Steen Hegelund
 <steen.hegelund@microchip.com>, Luca Ceresoli <luca.ceresoli@bootlin.com>,
 Nuno Sa <nuno.sa@analog.com>, Thomas Petazzoni
 <thomas.petazzoni@bootlin.com>,  stable@vger.kernel.org
Date: Thu, 29 Feb 2024 11:25:09 +0100
In-Reply-To: <20240229111430.54bdb6b1@bootlin.com>
References: <20240229083953.607569-1-herve.codina@bootlin.com>
	 <20240229083953.607569-3-herve.codina@bootlin.com>
	 <c2b830bb4a4cf76dec8783f38b2477120edb1a15.camel@gmail.com>
	 <20240229111430.54bdb6b1@bootlin.com>
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On Thu, 2024-02-29 at 11:14 +0100, Herve Codina wrote:
> On Thu, 29 Feb 2024 10:50:21 +0100
> Nuno S=C3=A1 <noname.nuno@gmail.com> wrote:
>=20
> > On Thu, 2024-02-29 at 09:39 +0100, Herve Codina wrote:
> > > In the following sequence:
> > > =C2=A0 1) of_platform_depopulate()
> > > =C2=A0 2) of_overlay_remove()
> > >=20
> > > During the step 1, devices are destroyed and devlinks are removed.
> > > During the step 2, OF nodes are destroyed but
> > > __of_changeset_entry_destroy() can raise warnings related to missing
> > > of_node_put():
> > > =C2=A0 ERROR: memory leak, expected refcount 1 instead of 2 ...
> > >=20
> > > Indeed, during the devlink removals performed at step 1, the removal
> > > itself releasing the device (and the attached of_node) is done by a j=
ob
> > > queued in a workqueue and so, it is done asynchronously with respect =
to
> > > function calls.
> > > When the warning is present, of_node_put() will be called but wrongly
> > > too late from the workqueue job.
> > >=20
> > > In order to be sure that any ongoing devlink removals are done before
> > > the of_node destruction, synchronize the of_overlay_remove() with the
> > > devlink removals.
> > >=20
> > > Fixes: 80dd33cf72d1 ("drivers: base: Fix device link removal")
> > > Cc: stable@vger.kernel.org
> > > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> > > ---
> > > =C2=A0drivers/of/overlay.c | 9 ++++++++-
> > > =C2=A01 file changed, 8 insertions(+), 1 deletion(-)
> > >=20
> > > diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> > > index 2ae7e9d24a64..99659ae9fb28 100644
> > > --- a/drivers/of/overlay.c
> > > +++ b/drivers/of/overlay.c=C2=A0=20
> >=20
> > In the cover, you mention device.h inclusion but I'm not seeing it? Thi=
s is
> > clearly up to the DT maintainers to decide but, IMHO, I would very much
> > prefer
> > to see fwnode.h included in here rather than directly device.h (so yeah=
,
> > renaming the function to fwnode_*). But yeah, I might be biased by own
> > series :)
> >=20
>=20
> Damned. I missed device.h in this patch.
> Without this one, the patch do not compile :(
>=20
> A fixup commit I missed to squash before sending.
>=20
> A v3 is planned to add this device.h.
>=20
> Nuno, do you prefer I wait few days before sending this v3 waiting for mo=
re
> replies
> or I send it right now and you re-do your comment on the v3 ?
>=20
> I would really prefer to send it now :)
>=20

Typically maintainers don't like much of re-spinning versions too fast. Tha=
t
said, up to you :). I can copy paste my comments in v3.

- Nuno S=C3=A1