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From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Linus Walleij <linus.walleij@linaro.org>,
	Russell King <linux@armlinux.org.uk>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH 2/2] ARM: integrator: impd1: use struct_size() in devm_kzalloc()
Date: Fri, 4 Jan 2019 11:18:51 -0600
Message-ID: <9005dbee894cfbada5e57d6ddda9fdf4d711b0a4.1546621488.git.gustavo@embeddedor.com> (raw)
In-Reply-To: <cover.1546621488.git.gustavo@embeddedor.com>

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
    int stuff;
    void *entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 arch/arm/mach-integrator/impd1.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-integrator/impd1.c b/arch/arm/mach-integrator/impd1.c
index eb0149561be2..8ccf01af3817 100644
--- a/arch/arm/mach-integrator/impd1.c
+++ b/arch/arm/mach-integrator/impd1.c
@@ -389,8 +389,8 @@ static int __ref impd1_probe(struct lm_device *dev)
 			char *chipname;
 			char *mmciname;
 
-			lookup = devm_kzalloc(&dev->dev,
-					      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
+			lookup = devm_kzalloc(&dev->deva,
+					      struct_size(lookup, table, 3),
 					      GFP_KERNEL);
 			if (!lookup)
 				return -ENOMEM;
-- 
2.20.1


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  parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-04 17:13 [PATCH 0/2] Fix NULL pointer dereference and use struct_size Gustavo A. R. Silva
2019-01-04 17:17 ` [PATCH 1/2] ARM: integrator: impd1: fix NULL pointer dereference Gustavo A. R. Silva
2019-01-11 12:22   ` Linus Walleij
2019-01-04 17:18 ` Gustavo A. R. Silva [this message]
2019-01-05  5:26   ` [PATCH 2/2] ARM: integrator: impd1: use struct_size() in devm_kzalloc() kbuild test robot

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