2018-08-23 19:34:58

by Gustavo A. R. Silva

Subject: [PATCH] mtd: rawnand: jz4780: 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);

Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/mtd/nand/raw/jz4780_nand.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/jz4780_nand.c b/drivers/mtd/nand/raw/jz4780_nand.c
index db4fa60..ac62395 100644
--- a/drivers/mtd/nand/raw/jz4780_nand.c
+++ b/drivers/mtd/nand/raw/jz4780_nand.c
@@ -352,7 +352,7 @@ static int jz4780_nand_probe(struct platform_device *pdev)
return -ENODEV;
}

- nfc = devm_kzalloc(dev, sizeof(*nfc) + (sizeof(nfc->cs[0]) * num_banks), GFP_KERNEL);
+ nfc = devm_kzalloc(dev, struct_size(nfc, cs, num_banks), GFP_KERNEL);
if (!nfc)
return -ENOMEM;

--
2.7.4

2018-08-23 21:29:47

by Boris Brezillon

Subject: Re: [PATCH] mtd: rawnand: jz4780: use struct_size() in devm_kzalloc()

On Thu, 23 Aug 2018 14:33:32 -0500
"Gustavo A. R. Silva" <[email protected]> wrote:

> 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);

Oh, I didn't know about that one. That's nice!

>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>

Reviewed-by: Boris Brezillon <[email protected]>

> ---
> drivers/mtd/nand/raw/jz4780_nand.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/raw/jz4780_nand.c b/drivers/mtd/nand/raw/jz4780_nand.c
> index db4fa60..ac62395 100644
> --- a/drivers/mtd/nand/raw/jz4780_nand.c
> +++ b/drivers/mtd/nand/raw/jz4780_nand.c
> @@ -352,7 +352,7 @@ static int jz4780_nand_probe(struct platform_device *pdev)
> return -ENODEV;
> }
>
> - nfc = devm_kzalloc(dev, sizeof(*nfc) + (sizeof(nfc->cs[0]) * num_banks), GFP_KERNEL);
> + nfc = devm_kzalloc(dev, struct_size(nfc, cs, num_banks), GFP_KERNEL);
> if (!nfc)
> return -ENOMEM;
>

2018-08-23 21:52:26

by Kees Cook

Subject: Re: [PATCH] mtd: rawnand: jz4780: use struct_size() in devm_kzalloc()

On Thu, Aug 23, 2018 at 12:33 PM, Gustavo A. R. Silva
<[email protected]> wrote:
> 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);
>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>

Reviewed-by: Kees Cook <[email protected]>

-Kees

> ---
> drivers/mtd/nand/raw/jz4780_nand.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/raw/jz4780_nand.c b/drivers/mtd/nand/raw/jz4780_nand.c
> index db4fa60..ac62395 100644
> --- a/drivers/mtd/nand/raw/jz4780_nand.c
> +++ b/drivers/mtd/nand/raw/jz4780_nand.c
> @@ -352,7 +352,7 @@ static int jz4780_nand_probe(struct platform_device *pdev)
> return -ENODEV;
> }
>
> - nfc = devm_kzalloc(dev, sizeof(*nfc) + (sizeof(nfc->cs[0]) * num_banks), GFP_KERNEL);
> + nfc = devm_kzalloc(dev, struct_size(nfc, cs, num_banks), GFP_KERNEL);
> if (!nfc)
> return -ENOMEM;
>
> --
> 2.7.4
>



--
Kees Cook
Pixel Security

2018-09-04 21:59:58

by Miquel Raynal

Subject: Re: [PATCH] mtd: rawnand: jz4780: use struct_size() in devm_kzalloc()

Hi Gustavo,

"Gustavo A. R. Silva" <[email protected]> wrote on Thu, 23 Aug
2018 14:33:32 -0500:

> 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);
>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> drivers/mtd/nand/raw/jz4780_nand.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/raw/jz4780_nand.c b/drivers/mtd/nand/raw/jz4780_nand.c
> index db4fa60..ac62395 100644
> --- a/drivers/mtd/nand/raw/jz4780_nand.c
> +++ b/drivers/mtd/nand/raw/jz4780_nand.c
> @@ -352,7 +352,7 @@ static int jz4780_nand_probe(struct platform_device *pdev)
> return -ENODEV;
> }
>
> - nfc = devm_kzalloc(dev, sizeof(*nfc) + (sizeof(nfc->cs[0]) * num_banks), GFP_KERNEL);
> + nfc = devm_kzalloc(dev, struct_size(nfc, cs, num_banks), GFP_KERNEL);
> if (!nfc)
> return -ENOMEM;
>

Applied to nand/next.

Thanks,
Miquèl