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From:   Julia Lawall <Julia.Lawall@lip6.fr>
To:     CK Hu <ck.hu@mediatek.com>
Cc:     kernel-janitors@vger.kernel.org,
        Philipp Zabel <p.zabel@pengutronix.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/4] drm/mediatek: add missing of_node_puts
Date:   Sun, 13 Jan 2019 09:47:41 +0100
Message-Id: <1547369264-24831-2-git-send-email-Julia.Lawall@lip6.fr>
In-Reply-To: <1547369264-24831-1-git-send-email-Julia.Lawall@lip6.fr>
References: <1547369264-24831-1-git-send-email-Julia.Lawall@lip6.fr>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The device node iterators perform an of_node_get on each iteration, so a
jump out of the loop requires an of_node_put.

The semantic patch that fixes this problem is as follows
(http://coccinelle.lip6.fr):

// <smpl>
@@
local idexpression n;
expression e,e1;
identifier l;
@@

 for_each_child_of_node(e1,n) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  goto l;
)
   ...
 }
...
l: ... when != n
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 6422e99..b9205bf 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -522,12 +522,15 @@ static int mtk_drm_probe(struct platform_device *pdev)
 			comp = devm_kzalloc(dev, sizeof(*comp), GFP_KERNEL);
 			if (!comp) {
 				ret = -ENOMEM;
+				of_node_put(node);
 				goto err_node;
 			}
 
 			ret = mtk_ddp_comp_init(dev, node, comp, comp_id, NULL);
-			if (ret)
+			if (ret) {
+				of_node_put(node);
 				goto err_node;
+			}
 
 			private->ddp_comp[comp_id] = comp;
 		}