[PATCH] mac80211: correct size the argument to kzalloc in minstrel_ht

[PATCH] mac80211: correct size the argument to kzalloc in minstrel_ht

[Thomas Huehn]

msp has type struct minstrel_ht_sta_priv not struct minstrel_ht_sta.

Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
---
 net/mac80211/rc80211_minstrel_ht.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 2d1acc6..dc2b801 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -809,7 +809,7 @@ minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
 			max_rates = sband->n_bitrates;
 	}
 
-	msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
+	msp = kzalloc(sizeof(struct minstrel_ht_sta_priv), gfp);
 	if (!msp)
 		return NULL;
 
-- 
1.7.10.4

Re: [PATCH] mac80211: correct size the argument to kzalloc in minstrel_ht

[Julian Calaby]

Hi Thomas,

On Fri, Jun 29, 2012 at 9:28 AM, Thomas Huehn
<thomas@net.t-labs.tu-berlin.de> wrote:
> msp has type struct minstrel_ht_sta_priv not struct minstrel_ht_sta.
>
> Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
> ---
>  net/mac80211/rc80211_minstrel_ht.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
> index 2d1acc6..dc2b801 100644
> --- a/net/mac80211/rc80211_minstrel_ht.c
> +++ b/net/mac80211/rc80211_minstrel_ht.c
> @@ -809,7 +809,7 @@ minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
>                        max_rates = sband->n_bitrates;
>        }
>
> -       msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
> +       msp = kzalloc(sizeof(struct minstrel_ht_sta_priv), gfp);

Why not use sizeof(*msp)?

Thanks,

-- 
Julian Calaby

Email: julian.calaby@gmail.com
Profile: http://www.google.com/profiles/julian.calaby/
.Plan: http://sites.google.com/site/juliancalaby/

Re: [PATCH] mac80211: correct size the argument to kzalloc in minstrel_ht

[thomas]

Hi Julian,

Compiler wise both of our suggestions will lead to the same machine code.
So beside the matter of taste, I just followed the other overall usage
pattern of kzalloc in minstrel_ht.
And it seems to be explicitly using the struct type.

Bye Thomas

Julian Calaby schrieb:
> Hi Thomas,
>
> On Fri, Jun 29, 2012 at 9:28 AM, Thomas Huehn
> <thomas@net.t-labs.tu-berlin.de> wrote:
>> msp has type struct minstrel_ht_sta_priv not struct minstrel_ht_sta.
>>
>> Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
>> ---
>>  net/mac80211/rc80211_minstrel_ht.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
>> index 2d1acc6..dc2b801 100644
>> --- a/net/mac80211/rc80211_minstrel_ht.c
>> +++ b/net/mac80211/rc80211_minstrel_ht.c
>> @@ -809,7 +809,7 @@ minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
>>                        max_rates = sband->n_bitrates;
>>        }
>>
>> -       msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
>> +       msp = kzalloc(sizeof(struct minstrel_ht_sta_priv), gfp);
>
> Why not use sizeof(*msp)?
>
> Thanks,
>

Re: [PATCH] mac80211: correct size the argument to kzalloc in minstrel_ht

[Schrober]

On Thursday 28 June 2012 22:00:41 thomas wrote:
> Hi Julian,
> 
> Compiler wise both of our suggestions will lead to the same machine code.
> So beside the matter of taste, I just followed the other overall usage
> pattern of kzalloc in minstrel_ht.
> And it seems to be explicitly using the struct type.

http://lxr.linux.no/linux/Documentation/CodingStyle

                Chapter 14: Allocating memory

The kernel provides the following general purpose memory allocators:
kmalloc(), kzalloc(), kcalloc(), vmalloc(), and vzalloc().  Please refer to
the API documentation for further information about them.

The preferred form for passing a size of a struct is the following:

        p = kmalloc(sizeof(*p), ...);

The alternative form where struct name is spelled out hurts readability and
introduces an opportunity for a bug when the pointer variable type is changed
but the corresponding sizeof that is passed to a memory allocator is not.

Casting the return value which is a void pointer is redundant. The conversion
from void pointer to any other pointer type is guaranteed by the C programming
language.
-- 
Franz Schrober

Re: [PATCH] mac80211: correct size the argument to kzalloc in minstrel_ht

[thomas]

Schrober schrieb:

> On Thursday 28 June 2012 22:00:41 thomas wrote:
>> Hi Julian,
>>
>> Compiler wise both of our suggestions will lead to the same machine code.
>> So beside the matter of taste, I just followed the other overall usage
>> pattern of kzalloc in minstrel_ht.
>> And it seems to be explicitly using the struct type.
> 
> http://lxr.linux.no/linux/Documentation/CodingStyle
> 
>                 Chapter 14: Allocating memory
> 
> The kernel provides the following general purpose memory allocators:
> kmalloc(), kzalloc(), kcalloc(), vmalloc(), and vzalloc().  Please refer to
> the API documentation for further information about them.
> 
> The preferred form for passing a size of a struct is the following:
> 
>         p = kmalloc(sizeof(*p), ...);
> 
> The alternative form where struct name is spelled out hurts readability and
> introduces an opportunity for a bug when the pointer variable type is changed
> but the corresponding sizeof that is passed to a memory allocator is not.
> 
> Casting the return value which is a void pointer is redundant. The conversion
> from void pointer to any other pointer type is guaranteed by the C programming
> language.


Good to have this clarified. I will send a version 2.

Thx Thomas