From: Yong Wu <yong.wu@mediatek.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Will Deacon <will@kernel.org>, <iommu@lists.linux-foundation.org>,
<linux-mediatek@lists.infradead.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com>,
<mingyuan.ma@mediatek.com>, <yf.wang@mediatek.com>,
<libo.kang@mediatek.com>, <chengci.xu@mediatek.com>,
<youlin.pei@mediatek.com>, <anan.sun@mediatek.com>,
<xueqi.zhang@mediatek.com>, Guenter Roeck <groeck@chromium.org>,
"Dan Carpenter" <dan.carpenter@oracle.com>
Subject: Re: [PATCH v2 2/5] iommu/mediatek: Add error path for loop of mm_dts_parse
Date: Thu, 23 Jun 2022 09:54:44 +0800 [thread overview]
Message-ID: <a53c4a4d9922c9a3fc774976494dea6da1bd8daa.camel@mediatek.com> (raw)
In-Reply-To: <521ed82e-f213-f635-6f5e-3e35ff8cc020@arm.com>
On Thu, 2022-06-16 at 11:31 +0100, Robin Murphy wrote:
> On 2022-06-16 11:08, Yong Wu wrote:
> > On Thu, 2022-06-16 at 09:59 +0100, Robin Murphy wrote:
> > > On 2022-06-16 06:42, Yong Wu wrote:
> > > > The mtk_iommu_mm_dts_parse will parse the smi larbs nodes. if
> > > > the
> > > > i+1
> > > > larb is parsed fail(return -EINVAL), we should of_node_put for
> > > > the
> > > > 0..i
> > > > larbs. In the fail path, one of_node_put matches with
> > > > of_parse_phandle in
> > > > it.
> > > >
> > > > Fixes: d2e9a1102cfc ("iommu/mediatek: Contain MM IOMMU flow
> > > > with
> > > > the MM TYPE")
> > > > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > > > ---
> > > > drivers/iommu/mtk_iommu.c | 21 ++++++++++++++++-----
> > > > 1 file changed, 16 insertions(+), 5 deletions(-)
[snip..]
> > > > +err_larbnode_put:
> > > > + while (i--) {
> > > > + larbnode = of_parse_phandle(dev->of_node,
> > > > "mediatek,larbs", i);
> > > > + if (larbnode &&
> > > > of_device_is_available(larbnode)) {
> > > > + of_node_put(larbnode);
> > > > + of_node_put(larbnode);
> > > > + }
> > >
> > > This looks a bit awkward - could we not just iterate through
> > > data->larb_imu and put dev->of_node for each valid dev?
> >
> > It should work. Thanks very much.
> >
> > >
> > > Also, of_find_device_by_node() takes a reference on the struct
> > > device
> > > itself, so strictly we should be doing put_device() on those as
> > > well
> > > if we're bailing out.
> >
> > Thanks for this hint. A new reference for me. I will add it.
>
> In fact, thinking about it some more we may as well do the
> of_node_put()
> unconditionally immediately after the of_find_device_by_node() call,
of_node_put is called in component_release_of in the normal case, thus
we shouldn't call of_node_put unconditionally. Right?
(Sorry for reply late)
> so
> then it's *only* the device references we'd need to worry about
> cleaning
> up in the failure path.
>
> Robin.
next prev parent reply other threads:[~2022-06-23 2:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-16 5:41 [PATCH v2 0/5] iommu/mediatek: Improve safety from dts Yong Wu
2022-06-16 5:41 ` [PATCH v2 1/5] iommu/mediatek: Use dev_err_probe to mute probe_defer err log Yong Wu
2022-06-16 13:28 ` Matthias Brugger
2022-06-16 5:42 ` [PATCH v2 2/5] iommu/mediatek: Add error path for loop of mm_dts_parse Yong Wu
2022-06-16 8:59 ` Robin Murphy
2022-06-16 10:08 ` Yong Wu
2022-06-16 10:31 ` Robin Murphy
2022-06-23 1:54 ` Yong Wu [this message]
2022-06-23 10:08 ` Robin Murphy
2022-06-16 13:49 ` Matthias Brugger
2022-06-23 2:12 ` Yong Wu
2022-06-16 5:42 ` [PATCH v2 3/5] iommu/mediatek: Validate number of phandles associated with "mediatek, larbs" Yong Wu
2022-06-16 5:42 ` [PATCH v2 4/5] iommu/mediatek: Improve safety for mediatek, smi property in larb nodes Yong Wu
2022-06-16 5:42 ` [PATCH v2 5/5] iommu/mediatek: Remove a unused "mapping" which is only for v1 Yong Wu
2022-06-16 12:03 ` AngeloGioacchino Del Regno
2022-06-16 13:56 ` Matthias Brugger
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