linux-kernel - [PATCH] mux: core: Fix double get

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Message-Id: <20170831152245.14502-1-hdegoede@redhat.com>
Date:   Thu, 31 Aug 2017 17:22:45 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Peter Rosin <peda@...ntia.se>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] mux: core: Fix double get_device()

class_find_device already does a get_device on the returned device.
So the device returned by of_find_mux_chip_by_node is already referenced
and we should not reference it again (and unref it on error).

Also rename of_find_mux_chip_by_node to of_get_mux_chip_by_node to
make it clear that it returns a reference.

Signed-off-by: Hans de Goede <hdegoede@...hat.com>
---
 drivers/mux/core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/mux/core.c b/drivers/mux/core.c
index 7aa656ac8fb5..8864cc745506 100644
--- a/drivers/mux/core.c
+++ b/drivers/mux/core.c
@@ -433,7 +433,7 @@ static int of_dev_node_match(struct device *dev, const void *data)
 	return dev->of_node == data;
 }
 
-static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np)
+static struct mux_chip *of_get_mux_chip_by_node(struct device_node *np)
 {
 	struct device *dev;
 
@@ -471,7 +471,7 @@ static struct mux_control *of_mux_control_get(struct device *dev,
 		return ERR_PTR(ret);
 	}
 
-	mux_chip = of_find_mux_chip_by_node(args.np);
+	mux_chip = of_get_mux_chip_by_node(args.np);
 	of_node_put(args.np);
 	if (!mux_chip)
 		return ERR_PTR(-EPROBE_DEFER);
@@ -480,6 +480,7 @@ static struct mux_control *of_mux_control_get(struct device *dev,
 	    (!args.args_count && (mux_chip->controllers > 1))) {
 		dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n",
 			np, args.np);
+		put_device(&mux_chip->dev);
 		return ERR_PTR(-EINVAL);
 	}
 
@@ -490,10 +491,10 @@ static struct mux_control *of_mux_control_get(struct device *dev,
 	if (controller >= mux_chip->controllers) {
 		dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n",
 			np, controller, args.np);
+		put_device(&mux_chip->dev);
 		return ERR_PTR(-EINVAL);
 	}
 
-	get_device(&mux_chip->dev);
 	return &mux_chip->mux[controller];
 }
 
-- 
2.13.4