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* [PATCH net-next] tulip: eeprom: use struct_size() in kmalloc()
@ 2019-01-31  0:33 Gustavo A. R. Silva
  2019-02-01 23:13 ` David Miller
  0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-31  0:33 UTC (permalink / raw)
  To: David S. Miller; +Cc: netdev, linux-parisc, linux-kernel, 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;
    struct boo entry[];
};

instance = kmalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);

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

instance = kmalloc(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>
---
 drivers/net/ethernet/dec/tulip/eeprom.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/dec/tulip/eeprom.c b/drivers/net/ethernet/dec/tulip/eeprom.c
index 1812f4916917..ba0a69b363f8 100644
--- a/drivers/net/ethernet/dec/tulip/eeprom.c
+++ b/drivers/net/ethernet/dec/tulip/eeprom.c
@@ -224,9 +224,7 @@ void tulip_parse_eeprom(struct net_device *dev)
 		        return;
 		}
 
-		mtable = kmalloc(sizeof(struct mediatable) +
-				 count * sizeof(struct medialeaf),
-				 GFP_KERNEL);
+		mtable = kmalloc(struct_size(mtable, mleaf, count), GFP_KERNEL);
 		if (mtable == NULL)
 			return;				/* Horrible, impossible failure. */
 		last_mediatable = tp->mtable = mtable;
-- 
2.20.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH net-next] tulip: eeprom: use struct_size() in kmalloc()
  2019-01-31  0:33 [PATCH net-next] tulip: eeprom: use struct_size() in kmalloc() Gustavo A. R. Silva
@ 2019-02-01 23:13 ` David Miller
  0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2019-02-01 23:13 UTC (permalink / raw)
  To: gustavo; +Cc: netdev, linux-parisc, linux-kernel

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Wed, 30 Jan 2019 18:33:55 -0600

> 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[];
> };
> 
> instance = kmalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);
> 
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
> 
> instance = kmalloc(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>

Applied.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2019-01-31  0:33 [PATCH net-next] tulip: eeprom: use struct_size() in kmalloc() Gustavo A. R. Silva
2019-02-01 23:13 ` David Miller

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