linux-kernel - [PATCH 2/2] ARM: integrator: impd1: use struct_size() in devm

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

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@...eddedor.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