From a12085d13997ed15f745f33a0e01002541160179 Mon Sep 17 00:00:00 2001
From: Wen Yang <yellowriver2010@hotmail.com>
Date: Thu, 7 Feb 2019 03:50:55 +0000
Subject: [PATCH] mtd: rawnand: atmel: fix possible object reference leak

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@hotmail.com>
Suggested-by: Boris Brezillon <bbrezillon@kernel.org>
Reviewed-by: Boris Brezillon <bbrezillon@kernel.org>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/mtd/nand/raw/atmel/pmecc.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nand/raw/atmel/pmecc.c b/drivers/mtd/nand/raw/atmel/pmecc.c
index 555a74e15269..9d3997840889 100644
--- a/drivers/mtd/nand/raw/atmel/pmecc.c
+++ b/drivers/mtd/nand/raw/atmel/pmecc.c
@@ -876,23 +876,32 @@ static struct atmel_pmecc *atmel_pmecc_get_by_node(struct device *userdev,
 {
 	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 };