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mtd: rawnand: atmel: use struct_size() in devm_kzalloc()

PATCH Applied Gustavo A. R. Silva 4 participants 4 messages Aug 24, 2018 – Sep 4, 2018

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#0 lore raw

PATCH 1/1 mtd: rawnand: atmel: 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 issue was detected with the help of Coccinelle.

---
 drivers/mtd/nand/raw/atmel/nand-controller.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
drivers/mtd/nand/raw/atmel/nand-controller.c +1 -3
index a068b21..b17cfd0 100644
@@ -1586,9 +1586,7 @@ static struct atmel_nand *atmel_nand_create(struct atmel_nand_controller *nc,
 		return ERR_PTR(-EINVAL);
 	}
 
-	nand = devm_kzalloc(nc->dev,
-			    sizeof(*nand) + (numcs * sizeof(*nand->cs)),
-			    GFP_KERNEL);
+	nand = devm_kzalloc(nc->dev, struct_size(nand, cs, numcs), GFP_KERNEL);
 	if (!nand) {
 		dev_err(nc->dev, "Failed to allocate NAND object\n");
 		return ERR_PTR(-ENOMEM);
Signature · 1 line
2.7.4
Reviewed-by on v1 1/1
#1 lore raw
Quoted 11 lines · Gustavo A. R. Silva

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);

Quoted 8 lines

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 issue was detected with the help of Coccinelle.

-Kees

Quoted 22 lines
---
 drivers/mtd/nand/raw/atmel/nand-controller.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
drivers/mtd/nand/raw/atmel/nand-controller.c +1 -4
index a068b21..b17cfd0 100644
@@ -1586,9 +1586,7 @@ static struct atmel_nand *atmel_nand_create(struct atmel_nand_controller *nc,
                return ERR_PTR(-EINVAL);
        }
 
-       nand = devm_kzalloc(nc->dev,
-                           sizeof(*nand) + (numcs * sizeof(*nand->cs)),
-                           GFP_KERNEL);
+       nand = devm_kzalloc(nc->dev, struct_size(nand, cs, numcs), GFP_KERNEL);
        if (!nand) {
                dev_err(nc->dev, "Failed to allocate NAND object\n");
                return ERR_PTR(-ENOMEM);
--

2.7.4

Signature · 2 lines
Kees Cook
Pixel Security
#2 lore raw
In reply to Gustavo A. R. Silva

Hi Gustavo,

Quoted 11 lines · On Thu, 23 Aug 2018 20:09:38 -0500 "Gustavo A. R. Silva"…

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);

Quoted 8 lines

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 issue was detected with the help of Coccinelle.

Can we have all NAND controller drivers patched in a single patch instead of having one patch per-driver?

Thanks,

Boris

maintainer Applied
#3 lore raw
In reply to Gustavo A. R. Silva

Hi Gustavo,

"Gustavo A. R. Silva" <[email protected]> wrote on Thu, 23 Aug 2018 20:09:38 -0500:

Quoted 14 lines

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:

Quoted 6 lines

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

This issue was detected with the help of Coccinelle.

---

Applied to nand/next.

Thanks,
Miqu?l