Subject: Re: [PATCH net-2.6.26 2/2] Do not allocate unneeded memory for dev->priv alignment.

From: Pavel Emelyanov <[email-masked]>
Date: Tue, 08 Apr 2008 12:42:27 +0400

Jarek Poplawski wrote:
> Pavel Emelyanov wrote, On 04/07/2008 06:31 PM:
> ...
> 
>> ---
>>  net/core/dev.c |    3 ++-
>>  1 files changed, 2 insertions(+), 1 deletions(-)
>>
>> diff --git a/net/core/dev.c b/net/core/dev.c
>> index 7aa0112..80e103a 100644
>> --- a/net/core/dev.c
>> +++ b/net/core/dev.c
>> @@ -4000,7 +4000,8 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
>>  	alloc_size = (sizeof(*dev) + NETDEV_ALIGN_CONST +
>>  		     (sizeof(struct net_device_subqueue) * (queue_count - 1))) &
>>  		     ~NETDEV_ALIGN_CONST;
>> -	alloc_size += sizeof_priv + NETDEV_ALIGN_CONST;
>> +	if (sizeof_priv)
>> +		alloc_size += sizeof_priv + NETDEV_ALIGN_CONST;
>>  
>>  	p = kzalloc(alloc_size, GFP_KERNEL);
>>  	if (!p) {
> 
> 
> IMHO this second "+ NETDEV_ALIGN_CONST" is needed here because of "~NETDEV_ALIGN_CONST".

Hmm, AFAIC, the net_device alignment is done earlier, while this one
makes sense in case the priv pointer alignment.

> Regards,
> Jarek P.