From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Andy Gross <andy.gross@linaro.org>,
David Brown <david.brown@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Jason Cooper <jason@lakedaemon.net>,
Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH] irqchip/qcom: Use struct_size() in devm_kzalloc()
Date: Wed, 27 Feb 2019 15:04:27 -0600 [thread overview]
Message-ID: <20190227210427.GA2844@embeddedor> (raw)
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;
struct boo entry[];
};
size = sizeof(struct foo) + count * sizeof(struct boo);
instance = alloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = alloc(struct_size(instance, entry, count), GFP_KERNEL)
Notice that, in this case, variable alloc_sz is not necessary, hence it
is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/irqchip/qcom-irq-combiner.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/irqchip/qcom-irq-combiner.c b/drivers/irqchip/qcom-irq-combiner.c
index 7f0c0be322e0..d269a7722032 100644
--- a/drivers/irqchip/qcom-irq-combiner.c
+++ b/drivers/irqchip/qcom-irq-combiner.c
@@ -237,7 +237,6 @@ static int get_registers(struct platform_device *pdev, struct combiner *comb)
static int __init combiner_probe(struct platform_device *pdev)
{
struct combiner *combiner;
- size_t alloc_sz;
int nregs;
int err;
@@ -247,8 +246,8 @@ static int __init combiner_probe(struct platform_device *pdev)
return -EINVAL;
}
- alloc_sz = sizeof(*combiner) + sizeof(struct combiner_reg) * nregs;
- combiner = devm_kzalloc(&pdev->dev, alloc_sz, GFP_KERNEL);
+ combiner = devm_kzalloc(&pdev->dev, struct_size(combiner, regs, nregs),
+ GFP_KERNEL);
if (!combiner)
return -ENOMEM;
--
2.21.0
next reply other threads:[~2019-02-27 21:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 21:04 Gustavo A. R. Silva [this message]
2019-06-04 23:16 [PATCH] irqchip/qcom: Use struct_size() in devm_kzalloc() Gustavo A. R. Silva
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