From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wolfgang Grandegger <wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org>
Subject: Re: [PATCH net-next-2.6 v3] can: Unify droping of invalid tx skbs
	and netdev stats
Date: Tue, 12 Jan 2010 09:44:36 +0100
Message-ID: <4B4C3674.7050609@grandegger.com>
References: <4B4BB1F9.3010808@hartkopp.net>
	<20100111.155537.166350032.davem@davemloft.net>
	<4B4C338B.7000808@hartkopp.net>
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Cc: socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
	David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
To: Oliver Hartkopp <socketcan-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
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Oliver Hartkopp wrote:
> David Miller wrote:
>> From: Oliver Hartkopp <socketcan-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
>> Date: Tue, 12 Jan 2010 00:19:21 +0100
>>
>>>  static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
>>>  {
>>> +	struct can_frame *cf = (struct can_frame *)skb->data;
>>>  	struct net_device_stats *stats = &dev->stats;
>>>  	int loop;
>>>  
>>> +	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
>>> +		kfree_skb(skb);
>>> +		stats->tx_dropped++;
>>> +		return NETDEV_TX_OK;
>>> +	}
>>> +
>>  ...
>>> +/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
>>> +static inline int can_dropped_invalid_skb(struct net_device *dev,
>>> +					  struct sk_buff *skb)
>>> +{
>>> +	const struct can_frame *cf = (struct can_frame *)skb->data;
>>> +
>>> +	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
>>> +		kfree_skb(skb);
>>> +		dev->stats.tx_dropped++;
>>> +		return 1;
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>  struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
>> Why are you not using the new helper function in vcan_tx()?
> 
> I just wanted the vcan driver keep off including "include/linux/can/dev.h"
> which is intended for 'real' CAN hardware.
> 
> As the vcan software devices do not need the bitrate-setting and skb echo
> handling from the driver library for real CAN devices, this inline function
> would be the only reason to include ".../dev.h"
> 
> But i don't have a strong preference to do it like this. Do you think i
> should change it to used the defined inline function?

Yes, for the sake of consistency.

Wolfgang.