[PATCH 4.14 183/209] mtd: rawnand: atmel: fix possible object reference leak

[Greg Kroah-Hartman]

From: Wen Yang <yellowriver2010@xxxxxxxxxxx>

commit a12085d13997ed15f745f33a0e01002541160179 upstream.

of_find_device_by_node() takes a reference to the struct device
when it finds a match via get_device, there is no need to call
get_device() twice.
We also should make sure to drop the reference to the device
taken by of_find_device_by_node() on driver unbind.

Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Signed-off-by: Wen Yang <yellowriver2010@xxxxxxxxxxx>
Suggested-by: Boris Brezillon <bbrezillon@xxxxxxxxxx>
Reviewed-by: Boris Brezillon <bbrezillon@xxxxxxxxxx>
Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Cc: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
Cc: Boris Brezillon <bbrezillon@xxxxxxxxxx>
Cc: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Brian Norris <computersforpeace@xxxxxxxxx>
Cc: Marek Vasut <marek.vasut@xxxxxxxxx>
Cc: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Cc: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mtd/nand/atmel/pmecc.c |   21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

--- a/drivers/mtd/nand/atmel/pmecc.c
+++ b/drivers/mtd/nand/atmel/pmecc.c
@@ -875,23 +875,32 @@ static struct atmel_pmecc *atmel_pmecc_g
 {
 	struct platform_device *pdev;
 	struct atmel_pmecc *pmecc, **ptr;
+	int ret;
 
 	pdev = of_find_device_by_node(np);
-	if (!pdev || !platform_get_drvdata(pdev))
+	if (!pdev)
 		return ERR_PTR(-EPROBE_DEFER);
+	pmecc = platform_get_drvdata(pdev);
+	if (!pmecc) {
+		ret = -EPROBE_DEFER;
+		goto err_put_device;
+	}
 
 	ptr = devres_alloc(devm_atmel_pmecc_put, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return ERR_PTR(-ENOMEM);
-
-	get_device(&pdev->dev);
-	pmecc = platform_get_drvdata(pdev);
+	if (!ptr) {
+		ret = -ENOMEM;
+		goto err_put_device;
+	}
 
 	*ptr = pmecc;
 
 	devres_add(userdev, ptr);
 
 	return pmecc;
+
+err_put_device:
+	put_device(&pdev->dev);
+	return ERR_PTR(ret);
 }
 
 static const int atmel_pmecc_strengths[] = { 2, 4, 8, 12, 24, 32 };